Strain-engineering in AlGaN/GaN HEMTs: impact of silicon nitride passivation layer on electrical performance

2021 ◽  
Author(s):  
Sanghamitra Das ◽  
Taraprasanna Dash ◽  
Devika Jena ◽  
Eleena Mohapatra ◽  
C K Maiti
Keyword(s):  
Experimental Data ◽  
Compressive Strain ◽  
Cutoff Frequency ◽  
Strain Engineering ◽  
Electrical Performance ◽  
Current Gain ◽  
Great Promise ◽  
High Electron ◽  
Wide Range ◽  
Gan Hemts

Abstract In this work, we present a physics-based analysis of two-dimensional electron gas (2DEG) sheet carrier density and other microwave characteristics such as transconductance and cutoff frequency of AlxGa1-xN/GaN high electron mobility transistors (HEMT). An accurate polarization-dependent charge control-based analysis is performed for microwave performance assessment in terms of current, transconductance, gate capacitances, and cutoff frequency of lattice-mismatched AlGaN/GaN HEMTs. The influence of stress on spontaneous and piezoelectric polarization is included in the simulation of an AlGaN/GaN HEMT. We have shown the change in threshold voltage (Vt) due to tensile and compressive strain with different gate lengths. Also, the influence of stress due to the change in nitride thickness is presented. Our simulation results for drain current, transconductance, and current-gain cutoff frequency for various gate length devices are calibrated and verified with experimental data over a wide range of gate and drain applied voltages, which are expected to be useful for microwave circuit design. The predicted transconductance, drain conductance, and operation frequency are quite close to the experimental data. The AlGaN/GaN heterostructure HEMTs with nitride passivation layers show great promise as a candidate in future high speed and high power applications.

Effect of GaN Cap Layer on the Electrical Properties of AlGaN/GaN HEMT

2012 ◽  
Vol 217-219 ◽  
pp. 2393-2396 ◽  
Author(s):  
Han Guo ◽  
Wu Tang ◽  
Wei Zhou ◽  
Chi Ming Li
Keyword(s):  
Electrical Properties ◽  
Doping Concentration ◽  
Cutoff Frequency ◽  
High Electron Mobility Transistor ◽  
Current Gain ◽  
High Electron ◽  
Saturation Current ◽  
Gan Hemt ◽  
Cap Layer ◽  
Dimensional Electron Gas

The electrical properties of AlGaN/GaN heterojunction high electron mobility transistor (HEMT) are simulated by using sentaurus software. This paper compares two structures, the HEMT with GaN cap layer and the HEMT without GaN cap layer. The sentaurus software simulates the DC and AC characteristics of the two AlGaN/GaN HEMT structures. The HEMT with GaN cap layer can increase the maximum transconductance gm from 177ms/mm to 399ms/mm when the doping concentration of the cap layer is 3×1018cm-3 compared with the other structure under the same conditions. The simulation results indicate that the HEMT with cap layer can increase maximum transconductance gm, saturation current Ids, current-gain cutoff frequency fT, maximum oscillation frequency fmax and reduce the series resistance of the drain to source compared with the HEMT without GaN cap layer. The large Ids of the HEMT with cap layer is attributed to the increase of the concentration of two dimensional electron gas (2DEG). Moreover, the change of the doping concentration of the cap layer will affect the gm and Ids.

scholarly journals Scaling Behavior of Sub-100 nm InAlN/GaN HEMTs on Silicon for RF Applications

2021 ◽  
Author(s):  
Peng Cui ◽  
Yuping Zeng
Keyword(s):  
Cutoff Frequency ◽  
Equivalent Circuit Model ◽  
Scaling Behavior ◽  
Gate Length ◽  
High Electron ◽  
Intrinsic Parameters ◽  
Gan Hemt ◽  
Gan Hemts ◽  
Rf Applications ◽  
20 Nm

Abstract Due to the low cost and the scaling capability of Si substrate, InAlN/GaN high-electron-mobility transistors (HEMTs) on silicon substrate have attracted more and more attentions. In this paper, a high-performance 50-nm-gate-length InAlN/GaN HEMT on Si with a high on/off current (Ion/Ioff) ratio of 7.28 × 106, an average subthreshold swing (SS) of 72 mV/dec, a low drain-induced barrier lowing (DIBL) of 88 mV, an off-state three-terminal breakdown voltage (BVds) of 36 V, a current/power gain cutoff frequency (fT/fmax) of 140/215 GHz, and a Johnson’s figure-of-merit (JFOM) of 5.04 THz∙V is simultaneously demonstrated. The device extrinsic and intrinsic parameters are extracted using equivalent circuit model, which is verified by the good agreement between simulated and measured S-parameter values. Then the scaling behavior of InAlN/GaN HEMTs on Si is predicted using the extracted extrinsic and intrinsic parameters of devices with different gate lengths (Lg). It presents that a fT/fmax of 230/327 GHz can be achieved when Lg­ scales down to 20 nm with the technology developed in the study, and an improved fT/fmax of 320/535 GHz can be achieved on a 20-nm-gate-length InAlN/GaN HEMT with regrown ohmic contact technology and 30% decreased parasitic capacitance. This study confirms the feasibility of further improvement of InAlN/GaN HEMTs on Si for RF applications.

Electrical and Optical Characterization of Pseudomorphic AlGaAs/InGaAs High Electron Mobility Transistors

1991 ◽  
Vol 240 ◽  
Author(s):  
W. E. Winters ◽  
A. S. Yue ◽  
D. Streit
Keyword(s):  
Layer Thickness ◽  
Film Growth ◽  
High Electron Mobility Transistors ◽  
Electrical Performance ◽  
Current Gain ◽  
High Electron ◽  
Switching Speed ◽  
Double Crystal ◽  
Strained Layers ◽  
Electron Mobility Transistors

ABSTRACTAdvances in thin-film growth techniques have allowed the succesful fabrication of transistor devices, relying on heterostructure technology to enhance their electrical performance. Devices utilizing heterostructure epitaxy have demonstrated unity current-gain cut-off frequencies well in excess of 100 GHz and maximum oscillation frequencies beyond 200 GHz.In this paper, the AlGaAs/InGaAs pseudomorphic HEMT is studied. X-ray Double-Crystal Diffractometry and Low-Temperature Photoluminescence Spectroscopy are used to demonstrate that the InGaAs pseudomorphic layer thickness of the strained layers, did not degrade the device switching speed. This suggests that HEMT devices with higher indium contents may be permitted without having to reduce the InGaAs layer thickness due to strain accommodation requirements. Since the increase in In content lowers the electron and hole effective masses and raises the low-field mobility, higher cut-off frequencies should be possible.

Ultra-Wide Bandgap AlxGa1-xN Channel Transistors

2019 ◽  
Vol 28 (01n02) ◽  
pp. 1940009 ◽  
Author(s):  
Towhidur Razzak ◽  
Siddharth Rajan ◽  
Andrew Armstrong
Keyword(s):  
Current Density ◽  
High Current Density ◽  
Cutoff Frequency ◽  
Wide Bandgap ◽  
Current Gain ◽  
Breakdown Field ◽  
High Electron ◽  
Saturation Velocity ◽  
Rf Devices ◽  
Performance Results

High Al-composition AlxGa1-xN, an emerging class of materials, is gaining significant traction due to its high critical breakdown electric field exceeding that of GaN and high electron saturation velocity that is comparable to GaN. High Al-composition AlxGa1-xN holds promise for applications such as highly scaled next generation RF devices and power devices. However, significant strides remain to be made before AlxGa1-xN can take a share of the limelight. Encouraging progress has been made in recent years, including multiple reports of RF operation of AlxGa1-xN channel transistors with reported unity current gain cutoff frequency as high as 40 GHz, high current density devices with the maximum reported current density exceeding 600 mA/mm and reports of breakdown fields in lateral transistors that are almost 3× the reported breakdown field for GaN channel devices of similar dimensions. This paper focuses on the lateral devices demonstrated thus far and discusses breakthrough performance results achieved for AlxGa1-xN channel transistors together with the key challenges that are yet to be properly addressed. The paper starts with a discussion of contact formation to AlxGa1-xN films – the key difficulty of fabricating AlxGa1-xN transistors. This is followed by a discussion of the types of devices that are typically used. This is followed up with a discussion of the approach required to make high quality devices with AlxGa1-xN as a template together with some recent result highlights.

Design of Double Delta-Doped Al0.22Ga0.78As/In0.22Ga 0.78As Pseudomorphic HEMTs

2012 ◽  
Vol 229-231 ◽  
pp. 2007-2009 ◽  
Author(s):  
Zhi Ming Wang ◽  
Jin Chao Mou ◽  
Wei Hua Yu ◽  
Xin Lv
Keyword(s):  
Cutoff Frequency ◽  
High Electron Mobility Transistors ◽  
Current Gain ◽  
High Electron ◽  
Saturation Current ◽  
Structure Form ◽  
Electron Mobility Transistors ◽  
Saturation Current Density ◽  
Maximum Current ◽  
Simulation Results

In this study, performances of double delta-doped AlGaAs/InGaAspseudomorphic high electron mobility transistors are investigated. Simulation results demonstrate good performance for this structure. Form simulation, the structure demonstrates a maximum current gain cutoff frequency of 145GHz for 100nm gate length, a peak extrinsic transconductance of 526mS/mm, and a maximum saturation current density of 350mA/mm.

scholarly journals The Characteristics of 6-Inch GaN on Si RF HEMT with High Isolation Composited Buffer Layer Design

Electronics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 46
Author(s):  
Chong-Rong Huang ◽  
Chia-Hao Liu ◽  
Hsiang-Chun Wang ◽  
Hsuan-Ling Kao ◽  
Hsien-Chin Chiu ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Energy Band ◽  
Cutoff Frequency ◽  
High Electron Mobility Transistor ◽  
Buffer Layers ◽  
Current Gain ◽  
High Electron ◽  
Gas Channel ◽  
Conduction Energy Band ◽  
Gan On Si

In this study, a 50-nm Al0.05Ga0.95N back barrier (BB) layer was used in an AlGaN/GaN high-electron-mobility transistor between the two-dimensional electron gas channel and Fe-doped/C-doped buffer layers. This BB layer can reduce the channel layer. The BB layer is affected by doped carriers in the buffer layer and the conduction energy band between the channel and the buffer layers. The Ion/Ioff ratio of the BB device was 4.66 × 105, and the ratio for the device without BB was 1.91 × 103. Lower leakage currents were obtained in the BB device because of the higher conduction energy band. The 0.25-μm gate length device with the BB exhibited a high current gain cutoff frequency of 24.4 GHz, and power gain cutoff frequency of 73 GHz.

scholarly journals High-Performance InGaAs HEMTs on Si Substrates for RF Applications

Electronics ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 259
Author(s):  
Bo Wang ◽  
Yanfu Wang ◽  
Ruize Feng ◽  
Haomiao Wei ◽  
Shurui Cao ◽  
...  
Keyword(s):  
High Performance ◽  
Cutoff Frequency ◽  
Drain Current ◽  
High Electron Mobility Transistors ◽  
Current Gain ◽  
Gate Length ◽  
High Electron ◽  
Si Substrates ◽  
Electron Mobility Transistors ◽  
Inp Substrates

In this paper, we have fabricated InGaAs high-electron-mobility transistors (HEMTs) on Si substrates. The InAlAs/InGaAs heterostructures were initially grown on InP substrates by molecular beam epitaxy (MBE), and the adhesive wafer bonding technique was employed to bond the InP substrates to Si substrates, thereby forming high-quality InGaAs channel on Si. The 120 nm gate length device shows a maximum drain current (ID,max) of 569 mA/mm, and the maximum extrinsic transconductance (gm,max) of 1112 mS/mm. The current gain cutoff frequency (fT) is as high as 273 GHz and the maximum oscillation frequency (fMAX) reaches 290 GHz. To the best of our knowledge, the gm,max and the fT of our device are the highest ever reported in InGaAs channel HEMTs on Si substrates at given gate length above 100 nm.

scholarly journals Scaling Behavior of InAlN/GaN HEMTs on Silicon for RF Applications

2022 ◽  
Author(s):  
Peng Cui ◽  
Yuping Zeng
Keyword(s):  
Cutoff Frequency ◽  
Equivalent Circuit Model ◽  
Scaling Behavior ◽  
Gate Length ◽  
High Electron ◽  
Intrinsic Parameters ◽  
Gan Hemt ◽  
Gan Hemts ◽  
Rf Applications ◽  
20 Nm

Abstract Due to the low cost and the scaling capability of Si substrate, InAlN/GaN high-electron-mobility transistors (HEMTs) on silicon substrate have attracted more and more attentions. In this paper, a high-performance 50-nm-gate-length InAlN/GaN HEMT on Si with a high on/off current (Ion/Ioff) ratio of 7.28 × 106, an average subthreshold swing (SS) of 72 mV/dec, a low drain-induced barrier lowing (DIBL) of 88 mV, an off-state three-terminal breakdown voltage (BVds) of 36 V, a current/power gain cutoff frequency (fT/fmax) of 140/215 GHz, and a Johnson’s figure-of-merit (JFOM) of 5.04 THz∙V is simultaneously demonstrated. The device extrinsic and intrinsic parameters are extracted using equivalent circuit model, which is verified by the good agreement between simulated and measured S-parameter values. Then the scaling behavior of InAlN/GaN HEMTs on Si is predicted using the extracted extrinsic and intrinsic parameters of devices with different gate lengths (Lg). It presents that a fT/fmax of 230/327 GHz can be achieved when Lg­ scales down to 20 nm with the technology developed in the study, and an improved fT/fmax of 320/535 GHz can be achieved on a 20-nm-gate-length InAlN/GaN HEMT with regrown ohmic contact technology and 30% decreased parasitic capacitance. This study confirms the feasibility of further improvement of InAlN/GaN HEMTs on Si for RF applications.

LIQUIDUS THERMO-BAROMETER FOR THE MODELING OF MAGNETITE — MELT EQUILIBRIUM

2018 ◽  
pp. 71-80
Author(s):  
N. S. Aryaeva ◽  
E. V. Koptev-Dvornikov ◽  
D. A. Bychkov
Keyword(s):  
Experimental Data ◽  
Liquidus Temperature ◽  
Vertical Structure ◽  
Maximum Error ◽  
Silicate Melt ◽  
System Of Equations ◽  
Wide Range ◽  
Basaltic Melts ◽  
Multidimensional Statistics

A system of equations of thermobarometer for magnetite-silicate melt equilibrium was obtained by method of multidimensional statistics of 93 experimental data of a magnetite solubility in basaltic melts. Equations reproduce experimental data in a wide range of basalt compositions, temperatures and pressures with small errors. Verification of thermobarometers showed the maximum error in liquidus temperature reproducing does not exceed ±7 °C. The level of cumulative magnetite appearance in the vertical structure of Tsypringa, Kivakka, Burakovsky intrusions predicted with errors from ±10 to ±50 m.

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