The GaN based devices with respect to most parameters exceed the devices based on traditional semiconductor materials. The AlGaN-transistors are the devices, operating in the depletion mode. For most applications it is necessary to implement the operating mode E , when the current in the channel is closed at zero gate voltage. In this paper the novel method namely using the p -GaN layer under the gate has been considered. The plasma-chemical removal of p -GaN layer in the non-gated active region has been chosen as a formation method of this layer. In this case the challenges, namely the non-uniformity in the depth of etching and poor control of the etching rate, arise. To exclude these problems, the heterostructures with additional AlN barrier layer has been developed. The research results of the heterostructure parameters affecting the carrier concentration in the channel, and, respectively, the transistor output characteristics have been presented and the developed design process has been shown. According to it the normally-off transistors have been formed. The maximum drain current in the open state is 350 mA/mm at 4 V gate voltage and the breakdown voltage is about 550 V in closed state at 0 V gate voltage.
1. Гольцова М. Мощные GaN-транзисторы. Истинно революционная технология // Электроника: наука, технология, бизнес. 2012. № 4. С. 86–100.
2. 600-V normally off SiNx/AlGaN/GaN MISHEMT with large gate swing and low current collapse /
Z. Tang, Q. Jiang, Y. Lu et al. // IEEE Electron Device Letters. 2013. Vol. 34. No. 11. P. 1373–1375.
3. Asgari A., Kalafi M. The control of two-dimensional-electron-gas density and mobility in AlGaN/GaN heterostructures with Schottky gate // Materials Science and Engineering: C. 2006. Vol. 26. P. 898–901.
4. Tiwari S. Compound semiconductor device physics. Academic Press, San Diego, 1992, 32 p.
5. Landford W.B., Tanaka T., Otoki Y., Adesida I. Recessed-gate enhancement-mode GaN HEMT with high threshold voltage // Electronics Letters. 2005. Vol. 41. No. 7. P. 449–450.
6. Cai Y., Zhou Y., Lau K.M., Chen K.J. Control of threshold voltage of AlGaN/GaN HEMTs by fluoride-based plasma treatment: from depletion mode to enhancement mode // IEEE Trans. Electron Devices. 2006.
Vol. 53. No. 9. P. 2207–2215.
7. Ohmaki Y., Tanimoto M., Akamatsu S., Mukai T. Enhancement-mode AlGaN/AlN/GaN high electron mobility transistor with low on-state resistance and high breakdown voltage // Japanese Journal of Applied Physics. 2006. Vol. 45. No. 2. P. 42–45.
8. Kambayashi H., Satoh Y., Ootomo S. Over 100 A operation normally-off AlGaN-GaN hybrid
MOS-HFET on Si substrate with high-breakdown voltage // Solid-State Electronics. 2010. Vol. 54. No. 6.
P. 660–664.
9. Roccaforte F., Fiorenza P., Greco G. Recent advances on dielectrics technology for SiC and GaN power devices // Applied surface science. 2014. Vol. 301. P. 9–18.
10. Greco G., Iucolano F., Roccaforte F. Review of technology for normally-off HEMTs with p-GaN gate // Materials Science in Semiconductor Processing. 2018. Vol. 78. P. 96–106.
11. Uemoto Y., Hikita M., Ueno H. Gate Injection Transistor (GIT) – a normally-off AlGaN/GaN power transistor using conductivity modulation // IEEE Transactions on Electron Devices. 2007. Vol. 54. No. 12.
P. 3393–3399.
12. High-performance normally off p-GaN gate HEMT with composite AlN/Al0.17Ga0.83N/Al0.3Ga0.7N barrier layers design / H. Chiu, Y. Chang, B. Li at al. // Journal of the Electron Devices Society. 2018. Vol. 6.
P. 201–206.
13. Bai Z., Du J., Jiang Z., Yu Q. Design and simulation of high breakdown voltage AlGaN/GaN HEMTs with a charged passivation layer for microwave power applications // Journal of Computational Electronics. 2017. Vol. 16. No. 3. P. 741–747.
14. Mohamed A.A., Granzner R., Schwier F. Theoretical investigation of trigate AlGaN/GaN HEMTs // IEEE Transactions on Electron Devices. 2013. Vol. 60. P. 3335–3341.
15. High on/off ratio in enhancement-mode AlxGa1–xN/GaN junction heterostructure field-effect transistors with p-type GaN gate contact / T. Fujii, N. Tsuyukuchi, Y. Hirose et al. // Japanese Journal of Applied Physics. 2006. Vol. 45. No. 2. P. 37–41.
16. Adak S., Swain S., Rahaman H., Sarkar Ch. Effect of doping in p-GaN gate on DC performances of
AlGaN/GaN normally-off scaled HFETs // Devices for Integrated Circuit. 2017. P. 372–375.
17. Field- and current-driven degradation of GaN-based power HEMTs with p-GaN gate: Dependence on Mg-doping level / I. Rossetto, M. Meneghini, E. Canato et al. // Microelectronics Reliability. 2017. Vol. 76–77. P. 298–303.
18. Miyake H., Motogaito A., Hiramatsu K. Effects of reactor pressure on epitaxial lateral overgrowth of GaN via low-pressure metalorganic vapor phase epitaxy // Japanese Journal of Applied Physics. 1999. Vol. 38. No. 9A/B. P. L1000–L1002.