Martin Domeij

Fairchild Semiconductor | FAIRCHILDSEMI

Device lifetime under reverse bias conditions is an important reliability concern for SiC devices. Provided that the termination structure is well designed, device failure in the active cell is driven by gate oxide breakdown due to the high field in the semiconductor and gate dielectric. For planar MOSFETs, the largest field occurs in the JFET regi...

In this paper, 1.2 kV SiC trench MOSFET with deep P structure has been proposed to effectively shield the trench bottom oxide. The various design splits, such as N concentration between deep P and deep P to trench distance, were experimentally evaluated and TCAD simulations were performed to extract maximum oxide electric field at trench bottom. Ba...

With the capability to switch at high speed, there are important concerns about Parasitic Turn-On (PTO) when using SiC MOSFETs in switching applications with fundamental half-bridge configuration [1]. In this work, we present 1200V SiC planar MOSFETs with low specific ON-resistance (Rsp), fast switching characteristics and high immunity to PTO. The...

In this paper, the authors continue the experimental evaluation of bipolar degradation for different 1.2 kV SiC MOSFETs. All the devices are stressed by pulsed repetitive forward current through the body diode with current densities varying from 1000 A/cm² up to 5000A/cm². The 1.2 kV SiC MOSFETs are split into two major groups based on the differen...

Silicon Carbide is rapidly growing in the power electronics industry. This is fueled to a great degree by the adoption of electric cars and power electronics needed both inside the vehicle and to support the charging infrastructure. This attention from automotive industry comes with a clear spotlight on the cost, quality, and efficiency of SiC powe...

Bipolar degradation is a known problem in the development of SiC MOSFETs when the body diodes (p+ body/ n-drift layer) are forward biased. Mostly higher voltage classes like the 1.7 kV or 3.3 kV SiC MOSFETs have been studied in literature resulting with significant Rdson increase [1-2]. In this work, body diode stress was conducted for 1.2kV SiC MO...

In this work, we investigate the Body Diode (BD) of a 40mOhm, 1.2kV SiC MOSFETs. We performed DC measurements and switching measurements, at Room Temperature (RT) and High Temperature (HT) (T=175°C), together with TCAD simulation and calibration. In switching measurements, we focused on the low side (LS) switch turn-on event, i.e., the BD turn-off...

Similar charge to failure distributions with mean values of about 50 C/cm ² were measured for planar SiC MOSFETs and MOS capacitors. Fast occurring and saturating negative flatband and threshold voltage drops were found in time resolved 1 second long pulsed gate current stress with I G =1 mA/cm ² at T=150 °C. No substantial difference in V TH drift...

In this work, body diode stress has been carried out for 1700 V 25 mΩ planar SiC MOSFETs. The epitaxial wafers were mapped with Infra-Red photoluminescence (IR-PL) to determine and localize the exact number of basal plane dislocations present in the drift layers of each die. The SiC MOSFETs were then packaged in groups with individual BPD counts in...

This work details two approaches with multi-epitaxial growth to create a vertical superjunction structure made of alternating pillars. One approach is a chain of very high energy implants, the other uses a preferred implantation direction to achieve a channeled profile. The manufactured devices show a breakdown voltage of 1000 V for channeled, two-...

SiC Gate Oxide reliability characterization is a matter of capturing a wide variety of time scales and their impact: From performance changes to breakdown of the device.These time constants can be understood by using BTI, CVS and RVS. Some time constants are rather swift and require special test methods (e.g. BTI), while other time constants requir...

We have investigated the effect of high temperature annealing of phosphorus doped poly on gate oxide integrity and device reliability. In NMOS capacitance analysis, unstable flat band voltage characteristics and lower oxide breakdown electric field were observed in wafers which received high temperature poly annealing at 1100 °C. Gate oxide integri...

In this work, threshold voltage drift of SiC MOSFET devices have been investigated. The drift during positive gate bias application was found to be moderate for three commercial grade devices, while the results for negative gate bias application differ widely. We demonstrate ON Semiconductor SiC MOSFETs with threshold voltage stability under both p...

1200 V 80 mΩ SiC MOSFETs were developed for 150 mm wafer mass production. Avalanche ruggedness was confirmed by measuring the failure distribution in unclamped inductive switching (UIS) for five wafers. The high voltage blocking reliability was verified by running 1000hr high temperature reverse bias tests for totally 770 devices without failures....

Reliability characterisation of SiC devices is an ongoing activity. For this work, four different splits of opened and gel-filled, 1200 V SiC MOSFETs in TO247 housings were tested in H³TRB for almost 2000 hours with monitoring of the leakage currents. In addition, electrical measurements and visual inspection were performed at intermediate time-ste...

In this work, TCAD modeling of a 1200 V SiC MOSFET is presented. The main focus is on modeling of the channel mobility, and the Coulomb scattering by interface traps and surface roughness are therefore included. For the Coulomb scattering, the interface trap profiles have been extrapolated from the subthreshold characteristics at room temperature,...

Reliability characterisation of SiC devices is an ongoing activity. For this work, four different splits of opened and gel-filled, 1200 V SiC MOSFETs in TO247 housings were tested in H³TRB for almost 2000 hours with monitoring of the leakage currents. In addition, electrical measurements and visual inspection were performed at intermediate time-ste...

Lateral implanted SiC MOSFETs and NMOS capacitors were fabricated and used to extract channel mobility and interface state density D IT for three different gate oxides. D IT values were extracted using the high(1 MHz)-low(1 kHz) method for NMOS capacitors and the subthreshold slope for MOSFETs. The subthreshold slope extraction gave 6–20 times high...

In this work, the detection and characterization of various crystal defects in high doped silicon carbide by photoluminescence (PL) is explored. The detection of basal plane dislocations in high doped epitaxial buffer layers is demonstrated using the near ultraviolet (NUV) emission images. Several characteristic defects in high doped 150mm substrat...

Lateral SiC MOSFETs and NMOS capacitors were fabricated and electrically evaluated for channel mobility, DIT and gate oxide breakdown. Time resolved measurements of VTH and VFB drift during gate bias stress were performed resulting in logarithmic time dependence for moderate stress time and temperature. Gate bias stress was also carried out during...

Reliability and cost are the major factors facing large scale adoption of SiC power devices. The push to reduce costs with 150mm diameter wafers comes with lower crystal quality and higher defects, thus prompting reliability concerns. In this work we present ways for comprehensive detection and screening of bipolar degradation causing defects and o...

Silicon Carbide (SiC) Bipolar Junction Transistors (BJTs) are promising power devices for high power and high temperature applications. For the improvement of transient speeds, effect of the driver base capacitor and anti-saturation diode are studied. To outline their switching performances, SiC BJTs with a blocking voltage of 1200 V are characteri...

In this work, large area SiC BJTs with good long-term stability in 1000 hrs DC stress tests are demonstrated. It is also illustrated how wafer scanning techniques can be used to reject BJT dies with basal plane dislocations, thereby eliminating the risk for bipolar degradation.

Epoxy moulded power modules with a small footprint of 40 mm x 55 mm were fabricated with two switches, each consisting of six parallel 1200 V 50 A rated BJTs and Schottky diodes. The SiC-based power modules have very low on-resistance of 3.3 m Omega and a current gain of 80, both at room temperature. An inverter with specially designed drive circui...

The current gain degradation of 4H-SiC BJTs with no significant drift of the on-resistance is investigated. Electrical stress on devices with different emitter widths suggests that the device design can influence the degradation behavior. Analysis of the base current extrapolated from the Gummel plot indicates that the reduction of the carrier life...

Large (4.3 mm(2)) area SiC BJTs were demonstrated with a current gain of 117 and a specific on-resistance of 2.8 m Omega cm(2). The open-base and open-emitter breakdown voltages are stable and with margin sufficient for 1200 V blocking. Fast and tail-current free switching behaviour was shown with rise- and fall-times in the range of 10-30 ns and t...

Epitaxial Ti3GeC2 thin films were deposited on 4 degrees off-cut 4H-SiC(0001) using magnetron sputtering from high purity Ti, C, and Ge targets. Scanning electron microscopy and helium ion microscopy show that the Ti3GeC2 films grow by lateral step-flow with {11 (2) over bar0} faceting on the SiC surface. Using elastic recoil detection analysis, at...

Efficiency is becoming more and more important for the designers of power electronics today, as well as size and cost. In boost DC/DC converters, typically used in PV inverters and PFC circuits, increased switching frequency makes a big impact on both size and cost. Silicon Carbide (SiC) bipolar junction transistors (BJT's) offer low-loss high spee...

In this paper, implantation-free 4H-SiC bipolar junction transistors (BJTs) with a high breakdown voltage of 2800 V have been fabricated by utilizing a controlled two-step etched junction-termination extension in the epitaxial base layer. The small-area device shows a maximum direct-current (dc) gain of 55 at J_C = 0.33 A (J_C =...

The on-resistance of silicon carbide bipolar transistors is characterized and simulated. Output characteristics are compared at different base currents and different temperatures in order to validate the physical model parameters. A good agreement is obtained, and the key factors, which limit the improvement of R _ON, are identified. Surf...

In this letter, the dependence of current gain and base resistance on crystal orientations for single-finger 4H-SiC bipolar junction transistors (BJTs) is analyzed. Statistical evaluation techniques were also applied to study the effect of surface passivation and mobility on the performance of the devices. It is shown that BJTs with an emitter edge...

Silicon carbide (SiC) bipolar junction transistors (BJT's) are normally-off fast switching devices with very low collector-emitter voltages (U_CE), combining the best of properties from unipolar and bipolar technology. They switch fast with turnoffs from semi saturated state without current tails and have the same time extremely low satur...

SiC airs are very attractive for high power application, but long term stability is still problematic and it could prohibit commercial production of these devices. The aim of this paper is to investigate the current gain degradation in BJTs with no significant degradation of the on-resistance. Electrical measurements and simulations have been used...

In this work, implantation-free 4H-SiC bipolar transistors with two-zone etched-JTE and improved surface passivation are fabricated. This design provides a stable open-base breakdown voltage of 2.8 kV which is about 75% of the parallel plane breakdown voltage. The small area devices shows a maximum dc current gain of 55 at Ic=0.33 A (J(C)=825 A/cm(...

Vertical epitaxial NPN SiC BJTs for 1200 V rating were fabricated. Very low collector-emitter saturation voltages VCESAT=0.5 V at IC=6 A (JC=140 A/cm2) and T=25 °C and VCESAT=1.0 V at IC=6 A and T=250 °C were measured. The common emitter current gain at IC=6 A is 71 at T=25 °C and 32 at T=250 °C, respectively. A SPICE model was developed for the BJ...

An implantation-free 4H-SiC Darlington transistor with high current gain of 2900 (J_C = 970 A/cm² and V_CE = 6 V) at room temperature is reported. The device demonstrates a record maximum current gain of 640 at 200°C, offering an attractive solution for high-temperature applications. The monolithic Darlington device e...

In this brief, the electrical performance in terms of maximum current gain and breakdown voltage is compared experimentally and by device simulation for 4H-SiC BJTs passivated with different surface-passivation layers. Variation in bipolar junction transistor (BJT) performance has been correlated to densities of interface traps and fixed oxide char...

Epitaxial Ti3SiC2 (0001) thin film contacts were grown on doped 4H-SiC (0001) using magnetron sputtering in an ultra high vacuum system. The specific contact resistance was investigated using linear transmission line measurements. Rapid thermal annealing at 950 °C for 1 min of as-deposited films yielded ohmic contacts to n-type SiC with contact res...

Silicon carbide (SiC) bipolar junction transistors (BJT’s) are normally-off fast switching devices with very low collector-emitter voltages (VCE), combining the best of properties from unipolar and bipolar technology. They switch fast with turn-offs from semi saturated state without current tails and have the same time extremely low saturated UCE v...

Silicon carbide (SiC) bipolar junction transistors (BJTs) are normally-off devices which can block high voltages at high temperature operation. The SiC BJTs can be switched very fast with low losses [2] compared to BJT's made in silicon (Si), and can be operated at temperatures up to and above 250 °C. Vertical 1200V 20A rated high temperature capab...

Degradation of 4H-SiC power bipolar junction transistors (BJTs) under the influence of a high-energy helium ion beam was studied. Epitaxially grown npn BJTs were implanted with 3.0 MeV helium in the fluence range of 1010–1011 cm−2. The devices were characterized by their current–voltage (I–V) behaviour before and after the implantation, and the res...

The influence of the emitter-base geometry on the current gain has been investigated by means of measurements and simulations. Particular attention has been placed on the emitter width and on the distance between the emitter edge and the base contact. When the emitter width is decreased from 40 to 8 m, the current gain is reduced by 20%, whereas wh...

Radiation hardness is tested for 4H-SiC n-p-n bipo- lar junction transistors designed for 1200-V breakdown voltage by implanting MeV protons and carbon ions at different doses and energies. The current gain is found to be a very sensitive parameter, and a fluence as low as 1 × 107 cm−2 of 10 MeV 12C can be clearly detected in the forward-output cha...

The 4H-SiC bipolar junction transistors (BJT) are considered as efficient high power switching devices due to the ability of obtaining very low specific on-resistance compared to FET based devices. However, one drawback with the present high voltage BJTs is the relatively low current gain. To reduce the power required by the drive circuit, it is im...

This paper reports large active area (15 mm(2)) 4H-SiC BJTS with a low V(CESAT)=0.6 V at 1(C)=20 A (J(C)=133 A/cm(2)) and an open-base breakdown voltage BV(CEO)=2.3 kV at T=25 degrees C. The corresponding room temperature specific on-resistance R(SP.ON)=4.5 m Omega cm(2) is to the authors knowledge the lowest reported value for a large area SiC BJT...

SiC power bipolar junction transistors (BJTs), for high voltage applications, have been studied under elevated temperature and electrical stress conditions. Electroluminescence has been used to capture effects of defect motion and growth, in complete transistor structures, leading to a quantifiable degradation in the electrical performance. The obs...

The mechanisms of bipolar degradation in silicon carbide BJTs are investigated and identified. Bipolar degradation occurs as result of stacking fault (SF) growth within the low-doped collector region. A stacking fault blocks vertical current transport through the collector, driving the defective region into saturation. This results in considerable...

The current gain of 4H-SiC BJTs has been modeled using interface traps between SIC and SiO(2) to describe surface recombination, by a positive temperature dependence of the carrier lifetime in the base region and by bandgap narrowing in the emitter region. The interface traps have been modeled by one single level at 1 eV above the valence band, wit...

In this work, the electrical performance in terms of maximum current gain, ON-resistance and blocking capability has been compared for 4H-SiC BJTs passivated with different surface passivation layers. Variation in BJT performance has been correlated to densities of interface traps and fixed oxide charge, as evaluated through MOS capacitors. Six dif...

This paper reports measurements and simulations made on 1200V 6A Silicon carbide (SiC) bipolar junction transistors. A SPICE model for the transistor has been developed and verified by static and dynamic measurements. Fast switching and low on state losses have been measured and SPICE simulated on the component level. To further describe the impact...

Accurate physical modeling has been developed to describe the current gain of silicon carbide (SiC) power bipolar junction transistors (BJTs), and the results have been compared with measurements. Interface traps between SiC and SiO₂ have been used to model the surface recombination by changing the trap profile, capture cross section, an...

Silicon carbide (SiC) semiconductor devices for high power are becoming more mature and are now commercially available as discrete devices. Schottky diodes have been on the market since a few years but also bipolar junction transistors (BJTs), JFETs and MOSFETs are now reaching the market. The interest is rapidly growing for these devices in high p...

Silicon carbide (SiC) bipolar junction transistors (BJTs) are normally-off devices which can block high voltages at high temperature operation. The SiC BJTs can be switched very fast with low losses [2] compared to BJT's made in silicon (Si), and can be operated at temperatures up to and above 250 °C. Vertical 1200V 6A rated NPN SiC BJTs were fabri...

The effects during reverse recovery of pin power diodes are determined by free carriers and their interaction with the electric field. A density of free carriers higher than the background doping will easily occur in space-charge regions during reverse recovery of high-voltage silicon devices. As a result, a high electric-field strength combined wi...

Implantation-free mesa-etched 4H-SiC PiN diodes with a near-ideal breakdown voltage of 4.3 kV (about 80% of the theoretical value) were fabricated, measured, and analyzed by device simulation and optical imaging measurements at breakdown. The key step in achieving a high breakdown voltage is a controlled etching into the epitaxially grown p-doped a...

This paper addresses the performance of SiC NPN Bipolar Junction Transistors (BJTs) at high and low temperature. A current gain of 50 at room temperature was obtained which decreases to 25 at 275 °C. A maximum current gain (β) of 111 has been reported at -86 °C. At low temperature (below -86 °C), the current gain drops rapidly because of carrier fr...

In this study, high voltage blocking (2.7 kV) implantation-free SiC Bipolar Junction Transistors with low on-state resistance (12 mΩ•cm 2) and high common-emitter current gain of 50 have been fabricated. A graded base doping was implemented to provide a low resistive ohmic contact to the epitaxial base. This design features a fully depleted base la...

Ion implantation for selective doping of SiC is problematic due to damage generation during the process and low activation of dopants. In SiC bipolar junction transistor (BJT) the junction termination extension (JTE) can be formed without ion implantation using instead a controlled etching into the epitaxial base. This etched JTE is advantageous be...

This work focuses on Ni ohmic contacts to the C-face (backside) of n-type 4H-SiC substrates. Low-resistive ohmic contacts to the wafer backside are important especially for vertical power devices. Ni contacts were deposited using E-beam evaporation and annealed at different temperatures (700-1050 degrees C) in RTP to obtain optimum conditions for f...

This paper reports a 4H-SiC bipolar junction transistor (BJT) with a breakdown voltage (BV(CEO)) of 1200 V, a maximum current gain (beta) of 60 and the low on-resistance (R(sp-on))of 5.2 m Omega cm(2). The high gain is attributed to an improved surface passivation SiO(2) layer which was grown in N(2)O ambient in a diffusion furnace. The SiC BJTs wi...

This paper addresses the performance of SiC NPN Bipolar Junction Transistors (BJTs) at high and low temperature. A current gain of 50 at room temperature was obtained which decreases to 25 at 275 degrees C. A maximum current gain (beta) of 111 has been reported at -86 degrees C. At low temperature (below -86 degrees C), the current gain drops rapid...

In this study, high voltage blocking (2.7 kV) implantation-free SiC Bipolar Junction Transistors with low on-state resistance (12 m Omega-cm(2)) and high common-emitter current gain of 50 have been fabricated. A graded base doping was implemented to provide a low resistive ohmic contact to the epitaxial base. This design features a fully depleted b...

Ion implantation for selective doping of SiC is problematic due to damage generation during the process and low activation of dopants. In SiC bipolar junction transistor (BJT) the junction termination extension (JTE) can be formed without ion implantation using instead a controlled etching into the epitaxial base. This etched JTE is advantageous be...

High-voltage blocking (2.7-kV) implantation-free SiC bipolar junction transistors with low ON-state resistance (12 mOmegaldrcm²) and high common-emitter current gain of 50 have been fabricated. A graded-base doping was implemented to provide a low-resistive ohmic contact to the epitaxial base. This design features a fully depleted base l...

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To determine the maximum allowed power dissipation in a power transistor, it is important to determine the relationship between junction temperature and power dissipation. This work presents a new method for measuring the junction temperature in a SiC bipolar junction transistor (BJT) that is self-heated during DC forward conduction. The method als...

This paper reports a 4H-SiC bipolar junction transistor (BJT) with a breakdown voltage (BVCEO) of 1200 V, a maximum current gain (β) of 60 and the low on-resistance (Rsp-on)of 5.2 mΩcm 2. The high gain is attributed to an improved surface passivation SiO2 layer which was grown in N2O ambient in a diffusion furnace. The SiC BJTs with passivation oxi...

This work focuses on Ni ohmic contacts to the C-face (backside) of n-type 4H-SiC substrates. Low-resistive ohmic contacts to the wafer backside are important especially for vertical power devices. Ni contacts were deposited using E-beam evaporation and annealed at different temperatures (700-1050 degrees C) in RTP to obtain optimum conditions for f...

This paper describes successful fabrication of 4H-SiC bipolar junction transistors (BJTs) with a regrown extrinsic base layer and an etched junction termination extension (JTE). Large-area 4H-SiC BJTs measuring 1.8 times 1.8 mm (with an active area of 3.24 ) showed a common emitter current gain of 42, specific on-resistance of 9 , and open-base bre...

Bipolar junction transistors (BJTs) of 4H-SiC, with a low collector-emitter forward voltage drop V_CE have been fabricated without base contact implantation. A comparison of BJTs on the same wafer with and without base contact implantation shows less than 10% higher V_CE for the BJTs without base contact implantation. Omitting t...

Effects of surface recombination on the common emitter current gain have been studied in 4H-silicon carbide (SiC) bipolar junction transistors (BJTs) with passivation formed by conventional dry oxidation and with passivation formed by dry oxidation in nitrous oxide (N2O) ambient. A gradual reduction of the current gain was found after removal of th...

In this work, a 100 nm Ni layer was deposited on both Si-face and C-face of n-type doped low resistive (

This letter presents fabrication of a power 4H-SiC bipolar junction transistor (BJT) with a high open-base breakdown voltage BV_CEO ap 1200 V, a low specific on-resistance R _{SP_ON} ap 5.2 mOmegamiddotcm², and a high common-emitter current gain beta ap 60. The high gain of the BJT is attributed to reduced surface recom...

The effect of the different types of passivation layers on the current gain of SiC BJTs has been investigated. Measurements have been compared for BJTs passivated with thermal SiO2, plasma deposited (PECVD) SiO2 and BJTs without passivation. The maximum DC current gain of BJTs with thermal SiO2 was about 62 at I-c=20 mA and V-ce=40 V. On the other...

4H-SiC BJTs have been fabricated with varying geometrical designs. The maximum value of the current gain was about 30 at IC=85 mA, V CE=14 V and room temperature (RT) for a 20 μm emitter width structure. A collector-emitter voltage drop VCE of 2 V at a forward collector current 55 mA (JC = 128 A/cm2) was obtained and a specific on-resistance of 15....

In this paper, we have investigated how the specific on-resistance and common emitter current gain of SiC BJTs depend on the base contact resistance. The on-state characteristics of SiC BJTs were investigated before and after base contact annealing at different temperatures. The common emitter current gain and specific on-resistance was improved by...

Silicon carbide (SiC) power bipolar junction transistors are interesting competitors to Si IGBTs for 1200 V power electronics applications. Advantages of SiC BJTs are low collector-emitter saturation voltages, little stored charge and high temperature capability. In this work, SiC NPN power BJTs with common emitter current gains of 40 have been fab...

An experimental technique using optical excitation by a YAG laser pulse for studying avalanche injection in power devices is demonstrated. This technique enables the creation of high uniform excess carrier concentrations in an optically defined device volume, involving very little heating. A method for determining the onset of avalanche multiplicat...

This paper reports the fabrication of epitaxial 4H-SiC bipolar junction transistors (BJTs) with a maximum current gain beta = 64 and a breakdown voltage of 1100 V. The high beta value is attributed to high material quality obtained after a continuous epitaxial growth of the base-emitter junction. The current gain of the BJTs increases with increasi...

One important challenge in SiC Bipolar Junction Transistor (BJT) fabrication is to form good ohmic contacts to both n-type and p-type SiC. In this paper, we have examined contact study in a SiC BJT process with sputter deposition of titanium tungsten contacts to both n-type and p-type regions followed by annealing at different temperatures between...

Silicon carbide electronic devices are already commercially available in a few application areas such as high voltage rectifiers and emerging RF power amplifiers. Over the past 15 years a very rapid progress of both materials and device quality has been seen and is very encouraging for the near future application market. Prototype devices show amaz...

In this paper, we present a novel 3.3kV diode structure with controlled injection of backside holes, i.e. CIBH diode. This new diode structure features buried floating p layers at the cathode side. These p doped areas prevent the formation of high electric field strength at the nn⁺ junction and accordingly avoid the avalanche generation...

One important challenge in SiC Bipolar Junction Transistor (BJT) fabrication is to form good ohmic contacts to both n-type and p-type SiC. In this paper, we have examined contact study in a SiC BJT process with sputter deposition of titanium tungsten contacts to both n-type and p-type regions followed by annealing at different temperatures between...

This paper reports the fabrication of epitaxial 4H-SiC bipolar junction transistors (BJTs) with a maximum current gain beta = 64 and a breakdown voltage of 1100 V. The high beta value is attributed to high material quality obtained after a continuous epitaxial growth of the base-emitter junction. The current gain of the BJTs increases with increasi...

Silicon carbide NPN bipolar junction transistors were fabricated and a current gain exceeding 60 was obtained for a BJT with a breakdown voltage BVCEO=1100 V. A reduction of the current gain was observed after contact annealing at 950 degC and this was attributed to degradation of the oxide passivation. Device simulations with varying emitter dopin...

This paper reports the fabrication of epitaxial 4H-SiC bipolar junction transistors (BJTs) with a maximum current gain β=64 and a breakdown voltage of 1100 V. The high β value is attributed to high material quality obtained after a continuous epitaxial growth of the base-emitter junction. The BJTs show a clear emitter-size effect indicating that su...

a martind@imit.kth.se, b erikd@imit.kth.se, c hslee@imit.kth.se, d bellman@imit.kth.se, e ostling@imit.kth.se Abstract. The current gain (β) of 4H-SiC BJTs as function of collector current (I C) has been investigated by DC and pulsed measurements and by device simulations. A measured monotonic increase of β with I C agrees well with simulations usi...

4H-SiC BJTs were fabricated using epitaxial regrowth instead of ion implantation to form a highly doped extrinsic base layer necessary for a good base ohmic contact. A remaining p regrowth spacer at the edge of the base-emitter junction is proposed to explain a low current gain of 6 for the BJTs. A breakdown voltage of 1000 V was obtained for devic...