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R. Krithivasan,
P. W. Marshall,
M. Nayeem,
A. K. Sutton,
W.-M. Kuo, B. M. Haugerud,
L. Najafizadeh,
J. D. Cressler,
M. A. Carts,
C. J. Marshall,
D. L. Hansen,
K.-C. M. Jobe,
A. L. McKay,
G. Niu,
R. Reed,
B. A. Randall,
C/A. Burfield,
M. D. Lindberg,
B. K. Gilbert,
E. S. Daniel
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ABSTRACT: Shift registers featuring radiation-hardening-by-design (RHBD) techniques are realized in IBM 8HP SiGe BiCMOS technology. Both circuit and device-level RHBD techniques are employed to improve the overall SEU immunity of the shift registers. Circuit-level RHBD techniques include dual-interleaving and gated-feedback that achieve SEU mitigation through local latch-level redundancy and correction. In addition, register-level RHBD based on triple-module redundancy (TMR) versions of dual-interleaved and gated-feedback cell shift registers is also realized to gauge the performance improvement offered by TMR. At the device-level, RHBD C-B-E SiGe HBTs with single collector and base contacts and significantly smaller deep trench-enclosed area than standard C-B-E-B-C devices with dual collector and base contacts are used to reduce the upset sensitive area. The SEU performance of these shift registers was then tested using heavy ions and standard bit-error testing methods. The results obtained are compared to the unhardened standard shift register designed with CBEBC SiGe HBTs. The RHBD-enhanced shift registers perform significantly better than the unhardened circuit, with the TMR technique proving very effective in achieving significant SEU immunity
IEEE Transactions on Nuclear Science 01/2007; · 1.45 Impact Factor
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Tianbing Chen,
A.K. Sutton,
M. Bellini, B.M. Haugerud,
J.P. Comeau,
Qingqing Liang,
J.D. Cressler,
Jin Cai,
T.H. Ning,
P.W. Marshall,
C.J. Marshall
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ABSTRACT: Proton radiation effects in vertical SiGe HBTs fabricated on CMOS-compatible silicon-on-insulator (SOI) are investigated for the first time. Proton irradiation at 63 MeV is found to introduce base leakage current at low base-emitter voltage, delay the onset of Kirk effect at high injection, and increase the frequency response of SiGe HBTs on SOI. The latter two effects are in contrast to those found in conventional bulk SiGe HBTs. Proton irradiation also generates positive fixed oxide and interface charge in the buried oxide, which alters both M-1 and BV<sub>CEO</sub> in the SiGe HBT by modulating the electric field in the collector region.
IEEE Transactions on Nuclear Science 01/2006; · 1.45 Impact Factor
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ABSTRACT: We present the results of gamma irradiation on third-generation, 200 GHz SiGe HBTs. Pre- and post-radiation dc figures-of-merit are used to quantify the tolerance of the raised extrinsic base structure to Co-60 gamma rays for varying device geometries. Additionally, the impact of technology scaling on the observed radiation response is addressed through comparisons to second generation, 120 GHz SiGe HBTs. Comparisons to previous proton-induced degradation results in these 200 GHz SiGe HBTs are also made, and indicate that the STI isolation oxide of the device shows increased degradation following Co-60 irradiation. The EB spacer oxide, on the other hand, demonstrates increased susceptibility to proton damage. Low dose rate proton testing was also performed and indicate that although there is a proton dose rate effect present in these devices, it cannot fully explain the observed trends. Similar trends have previously been observed for buried oxides and isolation oxides in several MOS technologies and have been attributed to increased charge yield in these oxides for 1.2 MeV Co-60 gamma rays when compared to 63 MeV protons.
IEEE Transactions on Nuclear Science 01/2006; · 1.45 Impact Factor
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ABSTRACT: The effect of proton irradiation on operating voltage constraints in SiGe HBTs is investigated for the first time in 120 GHz and 200 GHz SiGe HBTs. A variety of operating bias conditions was examined during irradiation, including terminals grounded, terminals floating, and forward active (FA) bias operation. The excess base current degradation at 5.0×10<sup>13</sup> p/cm<sup>2</sup> was similar in all cases. BV<sub>CEO</sub> and BV<sub>CBO</sub> showed no significant signs of degradation with irradiation. We also investigated for the first time the impact of radiation on SiGe HBTs biased under so-called "unstable" conditions (i.e., operating point instabilities). In the case of unstable bias conditions, device degradation under proton exposure is significantly different than for stable bias, and bias conditions can play a significant role in the damage process, potentially raising issues from a hardness assurance perspective.
IEEE Transactions on Nuclear Science 01/2006; · 1.45 Impact Factor
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ABSTRACT: The effects of proton irradiation on the dc and ac properties of 130 nm Si CMOS technology are investigated. The impact of substrate bias is reported for the first time. Two different irradiation substrate conditions were used, yielding different results. A comparison is drawn between the present work and a previously reported 180 nm CMOS technology node.
Radiation Effects Data Workshop, 2005. IEEE; 08/2005
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S. Venkataraman, B.M. Haugerud,
Enhai Zhao,
B. Banerjec,
A. Sutton,
P.W. Marshall,
Chang-Ho Lee,
J.D. Cressler,
J. Laskar,
J. Papapolymerou,
A.J. Joseph
Reliability Physics Symposium, 2005. Proceedings. 43rd Annual. 2005 IEEE International; 02/2005
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ABSTRACT: We present the first study of the effects of radiation on low-frequency noise in a novel complementary (npn+pnp) silicon-germanium (SiGe) HBT BiCMOS technology. In order to manipulate the physical noise sources in these complementary SiGe HBTs, 63.3 MeV protons were used to generate additional (potentially noise-sensitive) trap states. The base currents of both the npn and pnp SiGe HBTs degrade with increasing proton fluence, as expected, although in general more strongly for the npn transistors than for the pnp transistors, particularly in inverse mode. For the pnp SiGe HBTs, irradiation has almost no effect on the 1/f noise to proton fluence as high as 5.0×10<sup>13</sup> p/cm<sup>2</sup>, while the npn SiGe HBTs show substantial radiation-induced excess noise. In addition, unlike for the pnp devices, which maintain an I<sub>B</sub><sup>2</sup> bias dependence, the 1/f noise of the post-irradiated npn SiGe HBTs change to a near-linear dependence on I<sub>B</sub> at low base currents following radiation. That suggests a fundamental difference in the noise physics between the two types of devices.
IEEE Transactions on Nuclear Science 01/2005; · 1.45 Impact Factor
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ABSTRACT: We report, for the first time, the impact of proton irradiation on fourth-generation SiGe heterojunction bipolar transistors (HBTs) having a record peak unity gain cutoff frequency of 350 GHz. The implications of aggressive vertical scaling on the observed proton tolerance is investigated through comparisons of the pre-and post-radiation ac and dc figures-of-merit to observed results from prior SiGe HBT technology nodes irradiated under identical conditions. In addition, transistors of varying breakdown voltage are used to probe the differences in proton tolerance as a function of collector doping. Our findings indicate that SiGe HBTs continue to exhibit impressive total dose tolerance, even at unprecedented levels of vertical profile scaling and frequency response. Negligible total dose degradation in β (0.3%), f<sub>T</sub> and f<sub>max</sub>(6%) are observed in the circuit bias regime, suggesting that SiGe HBT BiCMOS technology is potentially a formidable contender for high-performance space-borne applications.
IEEE Transactions on Nuclear Science 01/2005; · 1.45 Impact Factor
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ABSTRACT: The proton tolerance of SiGe heterojunction bipolar transistors (HBTs) fabricated on a variety of substrate materials is investigated for the first time. The present SiGe HBT BiCMOS technology represents only the second commercially-available SiGe process to be reported for radiation effects. SiGe HBT dc and ac performance is compared for devices fabricated on silicon-on-insulator (SOI), low resistivity, and high resistivity silicon substrates, and all are found to be total dose tolerant to multi-Mrad radiation levels. We also compare these radiation results to those previously reported for other commercially-available SiGe technologies.
IEEE Transactions on Nuclear Science 01/2005; · 1.45 Impact Factor
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ABSTRACT: Proton irradiation is used to probe the physics of 4H-silicon carbide (SiC) Schottky barrier diodes (SBDs) and negative channel metal oxide semiconductor (nMOS) capacitors for the first time. Both 4H-SiC SBD diodes and SiC MOS structures show excellent radiation tolerance under high-energy, high-dose proton exposure. Unlike for SiC JBS diodes, which show a strong increase in series resistance after proton irradiation, these SiC SBDs show very little forward bias I--V degradation after exposure to 63.3 MeV protons up to a fluence of 5×10<sup>13</sup> p/cm<sup>2</sup>. An improvement in reverse leakage current after irradiation is also observed, which could be due to a proton annealing effect. The small but observable increase in blocking voltage for these SiC SBDs is attributed to a negative surface charge increase, consistent with earlier gamma results. The resultant Q<sub>eff</sub> change of 4H-SiC nMOS capacitors under proton irradiation was used to quantify the radiation induced changes to the blocking voltage in the SBD diodes in MEDICI simulations, and showed a good agreement with the experimental data. Characterization of these capacitors also suggests that 4H-SiC MOS structures are radiation hard.
IEEE Transactions on Nuclear Science 01/2005; · 1.45 Impact Factor
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Wei-Min Lance Kuo,
Yuan Lu,
B.A. Floyd, B.M. Haugerud,
A.K. Sutton,
R. Krithivasan,
J.D. Cressler,
B.P. Gaucher,
P.W. Marshall,
R.A. Reed,
G. Freeman
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ABSTRACT: This work presents the first experimental results on the effects of 63.3 MeV proton irradiation on 60 GHz monolithic point-to-point broadband space data link transceiver building blocks implemented in a 200 GHz SiGe heterojunction bipolar transistor (HBT) technology. A SiGe low-noise amplifier and a SiGe voltage-controlled oscillator were each irradiated to proton fluences of 5.0×10<sup>13</sup> p/cm<sup>2</sup>. The device and circuit level performance degradation associated with these extreme proton fluences is found to be minimal, suggesting that such SiGe HBT transceivers should be robust from a proton tolerance perspective for space applications, without intentional hardening at either the device or circuit level.
IEEE Transactions on Nuclear Science 01/2005; · 1.45 Impact Factor
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ABSTRACT: This paper examines, for the first time, the effects of radiation on transmission lines implemented in a commercial SiGe heterojunction bipolar transistor (HBT) bipolar complementary metal oxide semiconductor (BiCMOS) technology. Two different types of mm-wave transmission lines were designed, fabricated, and measured up to 110 GHz, and irradiated with 63.3 MeV protons to fluences as high as 5×10<sup>13</sup> p/cm<sup>2</sup>. The results demonstrate that radiation-induced changes are minimal in such lines, making them potentially suitable for use in space-based SiGe monolithic mm-wave communications systems.
IEEE Transactions on Nuclear Science 01/2005; · 1.45 Impact Factor
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ABSTRACT: The first results of the effects of mechanical planar biaxial tensile strain applied, post fabrication, to Si/SiGe HBT BiCMOS technology are reported in this work. Planar biaxial tensile strain was applied to the samples, which included both standard Si CMOS, SiGe HBT, and an epitaxial-base Si BJT control, for both first and second generation SiGe technologies. Device characterization was performed before and after strain, under identical conditions. At a strain level of 0.123%, increases in the saturation current as well as effective mobility are observed for the nFET. The Si BJT /SiGe HBT showed a consistent decrease in collector current and hence current gain after strain.
Silicon Monolithic Integrated Circuits in RF Systems, 2004. Digest of Papers. 2004 Topical Meeting on; 10/2004
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ABSTRACT: Device characteristics and analyses are reported for strained silicon n- and p-channel, metal-oxide-semiconductor field-effect transistors at five temperatures ranging from 296 to 367 K. Both partially depleted and bulk architectures were investigated. The devices were fabricated commercially on homogeneous silicon-based substrates and strain was applied mechanically after fabrication. Tensile uniaxial strain was applied within the elastic region using a back-end process. It was applied either parallel to or perpendicular to the carrier transport direction. Tensile biaxial strain was also induced in selected samples by using high thermal expansion Al substrates. Samples mounted on Al substrates experienced increasing strain as the temperature was raised. The structures were relaxed and characterized under steady-state conditions at each temperature level. No degradation of strain-induced mobility enhancement was observed due to increased temperature. We conclude that a reduction in average effective mass may be the greatest contribution to strain-enhanced mobility. © 2004 American Institute of Physics.
Journal of Applied Physics 02/2004; 95(5):2792-2796. · 2.17 Impact Factor
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ABSTRACT: Device characteristics and analysis are reported for strained silicon n- and p- channel partially depleted metal oxide semiconductor field effect transistors (MOSFETs) at 300 K. The devices were fabricated commercially on standard silicon-based silicon-on-insulator substrates and strain was applied mechanically after fabrication. Uniaxial tensile strain was applied within the elastic region using a back-end process and the relaxed structures were characterized under steady state conditions. Characterization was performed before and after straining. At ultralow strain levels (0.031%), pMOSFETs showed an increase in effective mobility μeff of 14.35% and an enhanced saturation current, Isat of 14.56%. An improvement in μeff of 15.19% and in Isat of 15.34% was observed for nMOSFETs strained by 0.039%. The latter die was debonded, released, and restressed at an elevated level of 0.052%. We observed an increased effective mobility μeff of 18.49% and Isat of 18.05%. Elastic uniaxial strain was fixed and characterization was performed at each strain level. The greatest mobility enhancement was observed for holes with strain applied at right angles to the channel length and applied field. © 2003 American Institute of Physics.
Journal of Applied Physics 09/2003; 94(6):4102-4107. · 2.17 Impact Factor
