The Effect of Channel Recess and Passivation on 4H-SiC MESFETs

2002 ◽  
Vol 742 ◽  
Author(s):  
Ho-Young Cha ◽  
Christopher I. Thomas ◽  
Goutam Koley ◽  
Lester F. Eastman ◽  
Michael G. Spencer
Keyword(s):  
Breakdown Voltage ◽  
Drain Current ◽  
Surface Effects ◽  
Gate Length ◽  
Small Signal ◽  
Saturation Current ◽  
Power Performance ◽  
Dc Characteristics ◽  
Signal Characteristics ◽  
Lower Saturation

ABSTRACTChannel-recessed 4H-SiC MESFETs were fabricated and demonstrated excellent small signal characteristics. A saturated current of 250 − 270 mA/mm at Vgs = 0 V and a maximum transconductance of 40 − 45 mS/mm were measured for channel-recessed devices with a gate length of 0.45 m. The three-terminal breakdown voltages (Vds) range from 120 V to 150 V. The Ft and Fmax of the 2 × 200 m devices were measured to be 14.5 GHz and 40 GHz, respectively. The channel recess technique results in a lower saturation current but higher breakdown voltage which makes it possible for the devices to operate at high voltages. Si3N4 passivation suppresses the instability in DC characteristics and improves CW power performance by reducing the surface effects. Less dispersion in the drain current during a power sweep was observed after passivation.

Correlation of Drain Current Pulsed Response with Microwave Power Output in AlGaN/GaN HEMTs

1999 ◽  
Vol 572 ◽  
Author(s):  
S. C. Binari ◽  
K. Ikossi-Anastasiou ◽  
W. Kruppa ◽  
H. B. Dietrich ◽  
G. Kelner ◽  
...  
Keyword(s):  
Power Output ◽  
Microwave Power ◽  
Drain Current ◽  
Current Response ◽  
Small Signal ◽  
Power Performance ◽  
Device Structure ◽  
Gan Hemt ◽  
Signal Characteristics ◽  
Power Densities

ABSTRACTThe drain-current response to short (<1μs) gate pulses has been measured for a series of GaN HEMT wafers that have similar dc and small-signal characteristics. This response has been found to correlate well with the measured microwave power output. For example, for devices where the pulsed drain current is greater than 70% of the dc value, output power densities of up to 2.3 W/mm are attained. This is in contrast with 0.5 W/mm measured for devices with low pulse response (less than 20% of the dc value). These results, which can be explained by the presence of traps in the device structure, provide a convenient test which is predictive of power performance.

AlGaN/GaN MIS-HEMTs with a p-GaN Cap Layer

MRS Advances ◽  
2017 ◽  
Vol 3 (3) ◽  
pp. 143-146
Author(s):  
Che-Ching Hsu ◽  
Pei-Chien Shen ◽  
Yi-Nan Zhong ◽  
Yue-Ming Hsin
Keyword(s):  
Leakage Current ◽  
Breakdown Voltage ◽  
Drain Current ◽  
Gate Insulator ◽  
Current Ratio ◽  
Dc Characteristics ◽  
Cap Layer

ABSTRACTIn this study, AlGaN/GaN MIS-HEMTs with a p-GaN cap layer and ALD deposited Al2O3 gate insulator were fabricated. Devices with two different thicknesses of p-GaN cap layers were investigated and compared. AlGaN/GaN MIS-HEMT with an 8-nm p-GaN cap showed a better DC characteristics than device with a 5-nm p-GaN cap. The drain current of 662.9 mA/mm, a high on/off current ratio of 2.67×109 and a breakdown voltage of 672 V were measured in device with an 8-nm p-GaN cap. In addition, lateral leakage current was investigated by using adjacent MIS gate structures with a separation of 3 μm to investigate the leakage current.

scholarly journals Comparison of Electrical Characterization of AlGaN/GaN HEMT with Multi-finger Gate

2021 ◽  
Author(s):  
Lijun He ◽  
Boyang Zhao ◽  
Chengyun He ◽  
Zhiyang Xie ◽  
Xing Long ◽  
...  
Keyword(s):  
Electronic Devices ◽  
Electrical Characterization ◽  
Drain Current ◽  
Gate Length ◽  
Saturation Current ◽  
Current Output ◽  
Gan Hemt ◽  
Accurate Comparison ◽  
Output Characteristics

Abstract This paper presents an exhaustive TCAD based comparison of the multi-gate and T-gate AlGaN/GaN HEMT. This paper simulates the DC and RF characteristics of the device and makes an accurate comparison. The important feature of the device such as threshold voltage, drain current output characteristics, transconductance, cut-off frequency, and maximum oscillation frequency were obtained. It is concluded that the shape optimization of the HEMT with multi-finger gates and the advantages over traditional T-gate devices. The device of two-finger gate with 50nm spacing has the best output characteristics, and its maximum saturation current is about 110% the size of the device of four-finger gate with 200nm at VGS=0V. And the gm and the gain of the device with 50nm spacing two-finger gate is 76mS/mm larger than the HEMT of three-finger gate with 200nm. In addition, we also conducted a simulation in the case of changing only refers to finger-gate length and cap-gate length. And it is concluded that the two-finger gate HEMT with 250nm finger-gate length and 2.0µm cap-gate length has the best output characteristics, which output current is 0.159 A/µm at VGS=-1.5V. The results show that AlGaN/GaN HEMT with multi-finger gate have great potential for high power and high frequency applications electronic devices.

scholarly journals A Novel 4H-SiC MESFET with a Heavily Doped Region, a Lightly Doped Region and an Insulated Region

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 488
Author(s):  
Hujun Jia ◽  
Mengyu Dong ◽  
Xiaowei Wang ◽  
Shunwei Zhu ◽  
Yintang Yang
Keyword(s):  
Breakdown Voltage ◽  
Direct Current ◽  
Oscillation Frequency ◽  
The Novel ◽  
Saturation Current ◽  
Excellent Performance ◽  
Maximum Oscillation Frequency ◽  
Power Added Efficiency ◽  
Novel Structure ◽  
Heavily Doped

A novel 4H-SiC MESFET was presented, and its direct current (DC), alternating current (AC) characteristics and power added efficiency (PAE) were studied. The novel structure improves the saturation current (Idsat) and transconductance (gm) by adding a heavily doped region, reduces the gate-source capacitance (Cgs) by adding a lightly doped region and improves the breakdown voltage (Vb) by embedding an insulated region (Si3N4). Compared to the double-recessed (DR) structure, the saturation current, the transconductance, the breakdown voltage, the maximum oscillation frequency (fmax), the maximum power added efficiency and the maximum theoretical output power density (Pmax) of the novel structure is increased by 24%, 21%, 9%, 11%, 14% and 34%, respectively. Therefore, the novel structure has excellent performance and has a broader application prospect than the double recessed structure.

scholarly journals Efficient symbolic computation of approximated small-signal characteristics of analog integrated circuits

1995 ◽  
Vol 30 (3) ◽  
pp. 327-330 ◽  
Author(s):  
P. Wambacq ◽  
F.V. Fernandez ◽  
G. Gielen ◽  
W. Sansen ◽  
A. Rodriguez-Vazquez
Keyword(s):  
Integrated Circuits ◽  
Symbolic Computation ◽  
Analog Integrated Circuits ◽  
Small Signal ◽  
Signal Characteristics

MESFETs on H-terminated Single Crystal Diamond

2009 ◽  
Vol 1203 ◽  
Author(s):  
Paolo Calvani ◽  
Maria Cristina Rossi ◽  
Gennaro Conte ◽  
Stefano Carta ◽  
Ennio Giovine ◽  
...  
Keyword(s):  
Performance Evaluation ◽  
Single Crystal ◽  
Oscillation Frequency ◽  
Diamond Films ◽  
Drain Current ◽  
Gate Length ◽  
Maximum Oscillation Frequency ◽  
Single Crystal Diamond ◽  
Device Geometry ◽  
Rf Performance

AbstractEpitaxial diamond films were deposited on polished single crystal Ib type HPHT diamond plates of (100) orientation by microwave CVD. The epilayers were used for the fabrication of surface channel MESFET structures having sub-micrometer gate length in the range 200-800 nm. Realized devices show maximum drain current and trasconductance values of about 190 mA/mm and 80 mS/mm, respectively, for MESFETs having 200 nm gate length. RF performance evaluation gave cut off frequency of about 14 GHz and maximum oscillation frequency of more than 26 GHz for the same device geometry.

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