The Effect of Ohmic Contact Location on the Buffer Leakage Current of AlGaN/GaN Heterostructure

2008 ◽  
Vol 600-603 ◽  
pp. 1337-1340
Author(s):  
Young Hwan Choi ◽  
Ji Yong Lim ◽  
Kyu Heon Cho ◽  
In Hwan Ji ◽  
Min Koo Han
Keyword(s):  
Buffer Layer ◽  
Leakage Current ◽  
Ohmic Contact ◽  
Lateral Diffusion ◽  
Drain Current ◽  
Gan Hemt ◽  
Cap Layer ◽  
Type C ◽  
Gan Heterostructure ◽  
Gan Buffer Layer

The effect of ohmic contact location on the buffer leakage current of AlGaN/GaN heterostructure was investigated and the AlGaN/GaN HEMT employing the proposed ohmic contact pattern was fabricated. We have fabricated 3 different types of ohmic patterns; type A - both contacts are on the etched GaN buffer layer, type B - one is on the etched GaN buffer layer and the other is on the unetched GaN cap layer and type C - both contacts are on the unetched GaN cap layer. Our experimental results showed that the ohmic contact on GaN buffer increased the buffer leakage current due to the lateral diffusion of ohmic metals. The proposed AlGaN/GaN HEMT successfully decreased the leakage current and did not affect the forward drain current and the transconductance.

Fabrication of AlGaN/GaN HFET with a High Breakdown Voltage on 4-inch Si (111) Substrate by MOVPE

2006 ◽  
Vol 955 ◽  
Author(s):  
Yuki Niiyama ◽  
Sadahiro Kato ◽  
Yoshihiro Sato ◽  
Masayuki Iwami ◽  
Jiang Li ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Breakdown Voltage ◽  
Field Effect Transistor ◽  
Drain Current ◽  
Growth Pressure ◽  
Si Substrates ◽  
Effect Transistor ◽  
Gan Heterostructure ◽  
Gan Film ◽  
Gan Buffer Layer

ABSTRACTWe investigated an AlGaN/GaN heterostructure field effect transistor (HFET) on Si substrates using a multi-wafer metalorganic vapor phase epitaxy (MOVPE) system. It was confirmed that a GaN film with smooth surface and without any crack was obtained. To increase a resistance of a GaN buffer layer, the carbon (C) -doping was carried out by controlling the V/III ratio and the growth pressure. The breakdown voltage of the buffer layer was dramatically improved by introducing the C. As a result, the breakdown voltage was about 900 V when the C concentration was about ∼8×1018 cm−3. After while, an AlGaN/GaN heterojunction FET (HFET) on a C-doped GaN buffer layer was fabricated. We achieved the breakdown voltage of over 1000 V and the maximum drain current of over 150 mA/mm, respectively. It was found that the C doped buffer layer is very effective for improving the breakdown voltage of AlGaN/GaN HFETs.

Low leakage current in AlGaN/GaN HFETs with preflow of Mg source before growth of u-GaN buffer layer

2011 ◽  
Vol 208 (7) ◽  
pp. 1607-1610 ◽  
Author(s):  
Yoshinori Oshimura ◽  
Takayuki Sugiyama ◽  
Kenichiro Takeda ◽  
Motoaki Iwaya ◽  
Tetsuya Takeuchi ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Leakage Current ◽  
Low Leakage ◽  
Low Leakage Current ◽  
Gan Buffer Layer

High Performance in a Normally-off Al2O3/GaN MOSFET Based on an AlGaN/GaN Heterostructure with a p-GaN Buffer Layer

2011 ◽  
Vol 58 (5(2)) ◽  
pp. 1500-1504 ◽  
Author(s):  
Dong-Seok Kim ◽  
Sung-Nam Kim ◽  
Ki-Won Kim ◽  
Ki-Sik Im ◽  
Hee-Sung Kang ◽  
...  
Keyword(s):  
Buffer Layer ◽  
High Performance ◽  
Gan Heterostructure ◽  
Gan Buffer Layer

ELECTRICAL PROPERTIES OF AlGaN/GaN HETEROSTRUCTURE FIELD-EFFECT TRANSISTORS (HFETs) WITH AND WITHOUT Mg-DOPED CARRIER CONFINEMENT LAYER

2010 ◽  
Vol 09 (04) ◽  
pp. 263-267
Author(s):  
A. Sh. HUSSEIN ◽  
Z. HASSAN ◽  
H. ABU HASSAN ◽  
S. M. THAHAB
Keyword(s):  
Electrical Properties ◽  
Leakage Current ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Drain Current ◽  
Carrier Confinement ◽  
Heterostructure Field Effect Transistors ◽  
Gan Heterostructure ◽  
Good Agreement ◽  
Mg Doped

AlGaN/GaN -based heterostructure field-effect transistors (HFETs) with and without Mg -doped semi-insulating carrier confinement layer were simulated by using ISE TCAD software, respectively. The detailed study on the electrical properties of these samples was performed. The effect of inserting Mg -doped GaN layer on the source–drain (S–D) leakage current was investigated. Higher values of drain current and extrinsic transconductance were achieved with conventional HFETs (without Mg -doped). The source-to-drain (S–D) leakage current of conventional HFETs was also higher. However, the S–D leakage current was reduced with the insertion of the Mg -doped semi-insulating carrier confinement layer. Our results are in good agreement with the experimental results obtained by other researchers.

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.

Fabrication and characterization of metal-ferroelectric-insulator-Si diodes and transistors with different HfSiON buffer layer thickness

2008 ◽  
Vol 23 (10) ◽  
pp. 2727-2732 ◽  
Author(s):  
Xubing Lu ◽  
Hiroshi Ishiwara ◽  
Kenji Maruyama
Keyword(s):  
Electrical Properties ◽  
Buffer Layer ◽  
Layer Thickness ◽  
Leakage Current ◽  
Drain Current ◽  
Memory Window ◽  
Buffer Layers ◽  
Window Width ◽  
Buffer Layer Thickness ◽  
The Impact

Metal-ferroelectric-insulator-Si (MFIS) structures using HfSiON as buffer layers were fabricated, and the impact of buffer layer thickness on the electrical properties of the MFIS devices was investigated. HfSiON films with thickness ranging from 1 to 4 nm were deposited by electron beam evaporation, which exhibited much reduced leakage current when compared to that of SiO2 with the same equivalent oxide thickness. From the viewpoint of polarization and charge injection, the flatband voltage and memory window width dependent on the sweeping voltages were discussed for the MFIS diodes with 1-, 2-, and 4-nm-thick HfSiON buffer layers. Small leakage current as well as excellent long-term data retention characteristics were found for all of these samples. It was also found that MFIS diodes with 2-nm-thick HfSiON buffer layer have the largest memory window width. Ferroelectric-gate transistors fabricated with a Pt/SBT(300nm)/HfSiON (2 nm)/Si gate structure showed a memory window of 0.8 V and a high drain current on/off ratio of 108 for the gate voltage sweep between +4 and −4 V. All of these excellent electrical properties proved that HfSiON acts as an excellent barrier for suppressing both leakage current and atomic interdiffusion.

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