GaN - Science topic

Fixed charges appear in the junction of semiconductor, you can assign traps in the material which may act like fixed charges.(follow the manual for traps section)

Thanks! I'll try that

Absorption is energy dependent so you need to specify the photon energy or wavelength.

The concept of non-ionizing energy loss (NIEL) has been demonstrated to be a successful approach to describe the displacement damage effects in silicon materials and devices. However, some discrepancies exist in the literature between experimental damage factors and theoretical NIELs. 60Co gamma rays having a low NIEL are an interesting particle source that can be used to validate the NIEL scaling approach. This paper presents different 60Co gamma ray NIEL values for silicon targets. They are compared with the radiation-induced increase in the thermal generation rate of carriers per unit fluence.

Has your problem solved for defining gate work function in case of P-GaN in contact with gate Please help me with this I am facing the same issue

Şükrü Aktaş Hello, Thank you for your answer, so can you please tell me what should I do to simulate NiO/Ga2O3 diode in TCAD Silvaco.

I am particular interestef in your research as it aligns with my current project on cyber security @Elshan Baghirov

Use only those models that are necessary and sufficient to represent the desired phenomenon.

"SUBSTRATE" is a parameter that defines a lattice constant for strain calculations, so it should be specified on the GaN region (in your case), not sapphire.

IMPACT SELF should be specified in a separate line, not in MODELS, if I'm not mistaken.

In case of convergence problems some tricks may be needed, such as switching to current boundary condition or transient simulation.

CONTACT NAME=Source WORKFUNCTION=$Wm

Set the mobility in the material really low

material region=3 mun=15

Eric Welch hey Eric , may you share, how you have managed to get particular coincidence angle between two surface ( as you mentioned in your query above) by using VESTA. I also want to study dynamics at boundaries of crystals structure.

Thank you

If you have the lattice parameters, you do not need to do an XRD measurement. The formula for lattice mismatch is simply the lattice parameter of one material minus the lattice parameter of the other divided by one of those parameters. For your example the mismatch would be (0.4760 - 0.3189)/0.4760 = 33% - which is huge; however, there are other sapphire and GaN orientations that are somewhat better matched (for which you would use the appropriate plane spacing for the R-cut or whatever it is), although the figure I see is about 16% (not sure what orientation) which is still very large. For the case of GaN and sapphire, people have successfully grown films with a buffer layer of some kind such as AlN (see J. Cryst. Growth vol. 178 pp 168 - 173 (1997) for ex.)

Amending my previous answer: You may be able to disperse GaN in liquid gallium (6.1 g/cc), or if you want it to float on top (also not to worry about the liquid freezing overnight), in galinstan (6.4 g/cc). Galinstan is a Ga-In-Sn eutectic that is used, among other uses, to replace mercury in medical thermometers. There are also a variety of heavier liquid alloys based on heavy metals such as Bi, In, Sn, and if toxicity is not a consideration, Pb, Cd and Tl. All those however melt considerably above room temperature and are likely to be inferior to Ga and galinstan with respect to wetting GaN.

Here's the solution to your query:

Haha, funny, so we switched sides. At around the same time, I built my first astable multi-vibrator using BC-238C transistors. I started off with electronics, building radios and all kind of electronic circuits to end up programming nowadays. Looks like you went the opposite way. :-)

Hey there, my fellow engineer Ravi Singh! So, you're diving into the exciting world of wire bonding on an Au/Ti/GaN stack, and it seems like you've hit a snag. No worries, I got your back. Now, let's tackle this wire bonding issue head-on.

1. **Ultrasonic Power and Force:**

Increasing ultrasonic power and reducing force might have been a suggestion, but it seems like it didn't cut it for you Ravi Singh. While it's a reasonable approach to optimize bonding parameters, the fact that it didn't work suggests there might be a more fundamental issue at play.

Have you Ravi Singh considered adjusting the bonding time or exploring alternative bonding techniques? Sometimes, a tweak in the process duration can make a significant difference.

2. **Stud Bumping Materials:**

You're curious about stud bumping with materials other than Au. Well, my friend, you're onto something. While Au is a common choice, depending on your application, you Ravi Singh might want to explore materials like Al, Cu, or even alloys. Each material has its own set of properties that might better suit your specific bonding requirements. Just ensure compatibility with your substrate.

Now, let's dig deeper into the root cause. The detachment of your metal stack could be linked to issues like poor adhesion or even material incompatibility. I'd recommend scrutinizing the metallurgical aspects, checking the surface cleanliness, and ensuring a proper intermetallic bond is formed during the bonding process.

Remember, the devil's in the details, and precision matters. Feel free to share more specifics, and we can unravel this wire bonding puzzle together. Good luck, and let's get those wires bonded seamlessly!

Hi Bassant

1- you should specify in parameter file:

ThermionicEmission {

Formula=1

}

or Formula =2 check in sdevice Manual for your material used !

do you now how to edit the parameter file?

2- for the convergence problem :

try to use a small Minstep => 1e-15 for exemple

Good luck

Younes

GaN HEMT'ler için tükenme bölgesinin drenaj tarafına doğru uzanması, GaN özelliklerinin başlangıç ve bitiş noktasının aynı özelliği taşıdığını gösterir.

Netaji Suvachintak thank you for the clarification.

What you have is hysterezis. The electric field is linear with the strain (and polarisation) until some value, then the electric field remains approximatively constant, when all the polarisation vectors inside the material are parallel (all the molecules of the material are polarized in the same direction).

The curves overlap because the hysterezis is an intrisic property of the material (at some electric field the polarisation remains almost constant with increasing field, that is all the molecules' polarisation vectors are oriented parallel).

When any two transistors are connected in parallel then it is not a Cascode configuration. In parallel connection conductance increases as mentioned by Mohammad Sajid Nazir. However, it should not be confused with Cascode connection where another transistor in common gate configuration works as a load for a common source transistor.

Thanks alot sir . Can you please explain how can we calculate the power (W/mm) of the HEMT device in silvaco TCAD

Peiran Wang Direction of Polarization is opposite with respect to one another. Top diagram has 2-DEG in AlGaN layer and lower one has it in GaN layer. Please use any standard example of SILVACO to compare your results.

Doping in Quantum Espresso supercell involves replacing some of the atoms in the original crystal structure with foreign atoms. To maintain the symmetry of the crystal structure while doping, it is essential to follow certain guidelines:

These guidelines should help you maintain the symmetry of the crystal structure while doping in Quantum Espresso supercell.

Shivansh Tripathi,

i think.... you have to modify mesh size of your structure.

Pavlo Sai thank you for the answer.

Aparna Sathya Murthy thank you for the publications. Especially the first one seems to correspond to my question very well!

Okay, thanks will try that, also I am facing an error that interface "region_1/region_2" is not found in the grid file, is meshing at that interface a solution to this?

Hai Wr

To obtain dislocation information from X-ray diffraction (XRD) data, you can use the Rietveld method. This method helps to determine the crystal structure of a material by refining the XRD patterns until the best fit is achieved. Additionally, you can use FullProf software to analyze the data and calculate the lattice parameters, strain and dislocation densities.

The parameter requirements vary with the particular method of simulation you are running for the device. I believe Sic material is already given in the material sets, but if you need to define yourself, the following you can add as primary steps. The commands are also be found in the command section for every given material. So, I also recommend you to check that out also,

material material=our_material eg300=A permittivity=B affinity=c nc300= D nv300=E mun=F mup=G

You can also check out the official manual book for more answers.

Dear sir,

I have designed a structure using sapphire as a subtsrate and now I want to replace sapphire substrate with Sic semi insulator what material parameters should I add for Sic in the simulation. Can you please guide me with this. Thanks in advance

How long ago was your last chamber cleaning? This might be due to redeposited material from the walls crumbling off and flying around in the plasma.

Thankyou sir, I'll go through manual.

Can you please send me one GaN hemt ID vS VDS/VGS matlab code for refrence.

Kindly see also the following useful RG links:

Muhammad Hamza El-Saba Thanks a lot. To follow up, Yes, I agree, direct carrier injection won’t happen. Indirectly the exposure will give rise to charg carriers. In Silvaco, will the Luminous module help in applying exposure and generate the carriers in AlGaN/GaN based Devices ?

Dear Netaji,

Can you show us this weird electric field profile? and why you consider it weird?

Prachi Pohekar Ma'am thankyou so much. I will do the same

Dear Manish Verma ,

I think the temperature may be out of the range

or also because there is a parameter which is out of the range of the floating numbers.

My proposal is to reduce the operating point such the power gets much smaller than your present input

Best wishes

L. Arivazhagan sir can you please provide the code by which you are getting the proper output and transfer characteristic as i am also facing the same issue.

quatum models have high dependency to your device dimensions and meshesh. you better to decrease the qfactor steps to solve the convergence problem. you can also use Bohm quantum potential model.

Thankyou so much Touati Zineeddine Sir

The current can supply externally with not any change in the existing current. In general, the leakage current wouldn't less inject external current won't affect performance.

ATLAS requires that the whole mesh area (defined x.mesh and y.mesh) is covered with regions. Use "air" or "vacuum" as a material for "material-free" regions.

Dear François Grandpierron ,

Physically the leakage current is due to tunneling and surface conduction. It may be also due to weak thin oxide regions that may enter into early breakdown. You can consult the book S.M.Sze, the physics of semicondcutor devices. It treats in details the non ideal currents in the oxides and insulators. In the simulators there are built in models for such nonideal current. In order to use them elaborately you have to study them b referring to these models and their model parameters. It can be modeled also phenomenologically by assuming a nonlinear resistor with the characteristics I=KV ^n both n and k can be used to fit the measures curves.

Best wishes

Dear François Grandpierron ,

In order to test your amplifier you bias the transistor at certain operating point and then apply different a punch of sinusoidal waveforms at the gate which increases gradually from 1.75 V to 4 in steps of 0.25 V. The frequency is 10 GHz, and the number of punches is = 10 and the duration is 10 cycles.

I do not no if there is other syntax of this operation! You have to return to the manual of of the software. The range of the values of Vgs depends on the DC operating point and the power supply voltage. The step defines the resolution of the required to the drain current and Th the drain to source voltage.

Best wishes

It is a bit tricky indeed. What typically used in such situations is MOSFET gate driver IC (I guess you need 30V ..40..50V rail-to-rail capable ) like https://ie.rs-online.com/web/p/gate-drivers/6684370 (many more models available beside it)

It is e.g. powered between +10V and -20V rail. You need to deliver logic signal to it, it can be done by optocoupler referenced to -20V . Power of 5V for it might be derived by linear regulator between 10V and -20V. Note the optocoupler may introduce some jitter. For experiments the rails might be delivered by lab supplies.

For knee voltage tune gate contact work function, AlGaN barrier thickness, 2 deg conc., Al mole fraction.

For on resistance tune ohmic contact resistance, mobility models.

Hi Mohammad,

Also take a look at this : https://shareok.org/bitstream/handle/11244/330132/2021_Joel_Shodamola_thesis.pdf?sequence=1 and

this:

you can try with ellipsometry (checking the refractive index).

I agree with Rüdiger Mitdank

Dear Kahtan Adnan Hussain ,

Hope you are well!

I replied your message.

Please see your message box.

Abdelhalim

Hello Pawan,

to get an Ohmic contact, the contact potential difference between the 2 materials must be low. Normally, in technological processes, Au-wires are used for contacting an element. The direct contact with Au gives a Schottky-barrier. To avoid this, a step of materials with increasing contact potentials is used. Titanium has the best differnce and gives low contact differences. Al with Ti gives an Ohmic contact too. Both materials are highly affin to oxygen, so an additional layer must be used. Furthermore, you want to realize a mechanical stable contact like Ni. Therefore in the next step Ni is used (if you want to investigate your structure in an magnetic field, you must avoid magnetic contacts but normally Ni is a usual material for the must purposes.) The upper layer is Au . It is chemically stable.

We use in our Lab the combination Ti/Al and bond with Al/Si wires. This gives sufficiently well Ohmic contacts, but not if you use Au-wires.

With Regard

R. Mitdank

Dear Kim Minho ,

If you can directly electrically probe the the 2DEG then you can measure its electrical properties as you did by the Van der Pauw method.

So, I propose that you can make the area of the deposited AlN layer smaller than the GaN substrate, slightly etch small grooves in the substrate at t he edges of the epitaxy layer and deposit in it a metal which can be connected to accessed by external probes. This metal will contact the 2DEG directly and in this way you access it electrically.

The other method is that you can use microwave absorption to determine the free carrier density in the gas. This is a contactless method for characterizing the semiconductors.

What I introduced here are proposals!

If you used any one of them please tell us!

Best wishes

Dear Abir,

Generally, no! But in your particular case of Si dopant (diamond structure) and GaN host, which is usually hexagonal wurtzite with lattice constant 1/ √2 of zincblende lattice constant, it is Ok. Note that a hexagonal wurtzite type, has nearly the same tetrahedral nearest-neighbor atomic coordination as cubic zincblende (ZB) and diamond structures.

Maybe you could show us the Ig-Vg curve.

Dear Abir,

The energy gap is inversely proportional to the dielectric constant and proportional to the number of atoms per cubic centimeter.

If your band gap decreases while epsilonr decrease then there must be a more pronounced decrease in the density of the atoms. Which means that the interatomic distance increases.

I would like rthat you follow my paper in the link:

Best wishes

Dear Chen Cai ,

If you show the structure of your transistor and the locations of the added sheet charges one can give specific answer.

But a conceptual answer is that in any capacitor structure charging one electrode by a charge Q must influence an equal and opposite sign charge at the other electrode.

Best wishes

Dear Rashid Jamal

Can you show a measured curve for such device?

I know this problem very well and I want that you reed elaborately my first proposal.

One of the solutions is not to scan the device b=voltage but have to force current in the device and solve for the voltage.

If you can not then you have to ass a series resistance to your device such that you obtain the I-V characteristics of the two devices in series and then you can easily subtract the voltage drop on the resistance.

The resistance is here to limit the device current when it enters in the break down.

As for the negative differential resistance it prefer the use of the consatnt voltage source.

So, adding the resistance may stabilize the operation of the device.

If you show me the measured I-V curve I can precise my answer more.

Best wishes

Mr. Filip’s arguments are convincing for me!

Did you mean Schottky barrier height?

The valence band ordering for the AlGaN alloys is discussed in

M. Feneberg et.al.

"Anisotropic optical properties of semipolar AlGaN layers grown on m-plane sapphire", May 2015

The properties of AlN are discussed here:

M. Feneberg et.al.

"Anisotropic absorption and emission of bulk ( 1 1 ¯ 00 ) AlN"

Ruediger

Dear Nudrat Sufiyan ,

thank you for your message.

I have attached a 10 min video regarding HEMT (recessed gate and conventional AlGaN/GaN HEMT) simulation code running on Deckbuild SILVACO ATLAS. There is no issue with "AlGaN_GaN_HEMT.in" SILVACO code.

You should study this code and related literature plus papers to get some parameters (impact material=GaN selb an1=2.9e8 an2=2.9e8 bn1=3.4e7 bn2=3.4e7 ap1=2.9e8 ap2=2.9e8 bp1=3.4e7 bp2=3.4e7) according to your case study and your reference paper!

The video is attached below.

Good luck with your work!

Best wishes,

Daniyal

I hope this article will help you. 10.3390/ma14040826

We have developed a model for calculating the dielectric function (refractive index) for every alloy composition in the InGaN system. It was published in chapter 5 of the Piprek book:

Best regards,

Ruediger

I recommend using the freeware BandEng, useful for computing III-nitride band structure and carrier profiles.

The standard material file includes GaN and AlGaN (including AlN, available by adjusting the AlGaN composition).

Additionally, it is possible to include user-defined materials, so you could experiment with lattice parameters and constants relating to piezoelectric polarization. You can also turn polarization off completely, and compare the results.

Good luck!

Thank you brother...

Dear Jayati Routh,

Check out the links below it may be useful

1. https://www.mdpi.com/1996-1944/12/10/1599/pdf-vor

2. https://core.ac.uk/download/pdf/293048893.pdf

Dear Joey P. C. Lin,

Check out the following links

1. http://oa.upm.es/48183/1/ZHAN_GAO.pdf

2. https://labs.dese.iisc.ac.in/msdlab/wp-content/uploads/sites/13/2019/01/Gallium-Nitride-GaN-High-Electron-Mobility-Transistors-HEMT.pdf

You can check the following bearing datasets (vibration signals Vs time):

PS: both of the dataset are treated in this paper :

IMS bearing : https://ti.arc.nasa.gov/tech/dash/groups/pcoe/

prognostic-data-repository/

Wind turbine high speed shaft data: https://www.mathworks.com/help/predmaint/ug/ wind-turbine-high-speed-bearing-prognosis.html

Palak Nath

Dear Paul Bisong ,

welocme!

You have to return to the manual of the Sentaurus software to see the cause of the hanging of the execution of the program.

This may be the systematic path to the solution.

May be a method to get rapidly acquainted to program is the study some of its tutorials especially those related to your device.

You will learn in a practical way how do you prepare an input simulation file for your device and how to run the simulation and how do you postprocess the results.

For the manual please look at the link: Sentaurus™ Device User Guide - ResearchGate

Best wishes