AlGaN/GaN HEMT의 채널폭 스케일링에 따른 협폭효과
Narrow channel effect on the electrical characteristics of AlGaN/GaN HEMT
0
조회
0
다운로드
1
인용
0
참고문헌
키워드
초록
본 연구에서는 AlGaN/GaN HEMT (High electron mobility transistor)를 제작하고 채널폭의 감소에 따른 특성의 변화를 고찰하였다. AlGaN/GaN 이종접합구조 기반의 기판 위에 채널의 길이는 1 ㎛, 채널 폭은 각각 0.5 ~ 9 ㎛가 되도록 전자선 리소그라피 방법으로 트랜지스터를 제작하였다. 게이트를 형성하지 않은 상태에서 채널의 면저항을 측정한 결과 sub-㎛ 크기로 채널폭이 작아짐에 따라 채널의 면저항이 급격히 증가하였으며, 트랜지스터의 문턱전압은 1.6 ㎛와 9 ㎛의 채널폭에서 -2.85 V 이었으며 0.9 ㎛의 채널폭에서 50 mV의 변화, 0.5 ㎛에서는 350 mV로 더욱 큰 변화를 보였다. 트랜스컨덕턴스는 250 mS/mm 내외의 값으로부터 sub-㎛ 채널에서 150 mS/mm 로 채널폭에 따라 감소하였다. 또한, 게이트의 역방향 누설전류는 채널폭에 따라 감소하였으나 sub-㎛ 크기에서는 감소가 둔화되었는데 채널폭이 작아짐에 따라 나타는 이와 같은 일련의 현상들은 AlGaN 층의 strain 감소로 인한 압전분극 감소가 원인이 되는 것으로 사료된다.
Abstract
AlGaN/GaN HEMTs (High electron mobility transistors) with narrow channel were fabricated and the effect of channel scaling on the device were investigated. The devices were fabricated using e-beam lithography to have same channel length of 1 ㎛ and various channel width from 0.5 to 9 ㎛. The sheet resistance of the channel was increased corresponding to the decrease of channel width and the increase was larger at the width of sub-㎛. The threshold voltage of the HEMT with 1.6 ㎛ and 9 ㎛ channel width was -2.85 V. The transistor showed a variation of 50 mV at the width of 0.9 ㎛ and the variation 350 mV at 0.5 ㎛. The transconductance of 250 mS/mm was decreased to 150 mS/mm corresponding to the decrease of channel width. Also, the gate leakage current of the HEMT decreased with channel width. But the degree of was reduced at the width of sub-㎛. It was thought that the variation of the electrical characteristics of the HEMT corresponding to the channel width came from the reduced Piezoelectric field of the AlGaN/GaN structure by the strain relief.
참고문헌 (9)
- D. Krausse, "AlGaN", GaN Power amplifiers for ISM applications, 2012, pp.74, 108~
- T. Oka, "AlGaN", GaN Recessed MIS-Gate HFET With High Threshold Voltage Normally-Off Operation for Power Electronics Applications, 2008, pp.29(7), 668~
- Vetury, R., "The Impact of Surface States on the DC and RF Characteristics of AlGaN", GaN HFETs, 2001, pp.48(3), 560~
- T. Palacios, "High-power AlGaN", GaN HEMTs for Ka-band applications, 2005, pp.26(11), 781~
- W. Saito, "Demonstration of 13.56-MHz Class-E Amplifier Using a High-Voltage GaN Power-HEMT", IEEE Electron Device Lett., 27(5), pp.326~ (2006)
- Ki-Sik Im, "Normally Off GaN MOSFET Based on AlGaN", GaN Heterostructure With Extremely High 2DEG Density Grown on Silicon Substrate, 2010, pp.31(3), 192~
- Naohisa Harada, "Formation of Recessed-Oxide Gate for Normally-Off AlGaN", GaN High Electron Mobility Transistors Using Selective Electrochemical Oxidation, 2011, pp.4, 021002~
- S. Maroldt, "Gate-recessed AlGaN", GaN based enhancement-mode high electron mobility transistors for high frequency operation, 2009, pp.48, 04~083
- O. Ambacher, "Two-dimensional electron gases induced by spontaneous and piezoelectric polarization charges in N- and Ga-face AlGaN", GaN heterostructure, 1999, pp.85(6), 3222~