HIGH-RATE ELECTRON-CYCLOTRON-RESONANCE ETCHING OF GAN, INN, AND AIN

Citation
Rj. Shul et al., HIGH-RATE ELECTRON-CYCLOTRON-RESONANCE ETCHING OF GAN, INN, AND AIN, Journal of vacuum science & technology. B, Microelectronics and nanometer structures processing, measurement and phenomena, 13(5), 1995, pp. 2016-2021
Citations number
24
Categorie Soggetti
Physics, Applied
ISSN journal
10711023
Volume
13
Issue
5
Year of publication
1995
Pages
2016 - 2021
Database
ISI
SICI code
1071-1023(1995)13:5<2016:HEEOGI>2.0.ZU;2-N
Abstract
Electron cyclotron resonance etch rates of GaN, InN, and AlN are repor ted as a function of pressure, microwave power, and radio-frequency (r f) power in a Cl-2/H-2/CH4/Ar plasma at 170 degrees C. The etch rates for GaN and InN increase as a function of rf power. Al 275 W, the etch rates reach maximum values of 2850 and 3840 Angstrom/min, respectivel y. These are the highest etch rates reported for these materials. As a function of pressure, the etch rates reach a maximum value at 2 mTorr and then decrease as the pressure is increased to 10 mTorr. The GaN a nd ALN etch rates increase less than a factor of 2 as the microwave po wer is increased from 125 to 850 W whereas the InN etch rate increases by more than a factor of 3.5. The maximum etch rate for AlN obtained in this study is 1245 Angstrom/min at a microwave power of 850 W, 1 mT orr pressure, and 225 W rf power. Atomic force microscopy is used to d etermine root-mean-square roughness as a function of etch conditions f or GaN and InN and, while very smooth pattern transfer can be obtained for a wide range of plasma conditions for GaN, the smoothness of the etched InN surface is more sensitive to rf power, microwave power, and process pressure. The surface composition of the GaN is characterized using Auger spectroscopy and has shown that the Ga:N ratio increases with increasing rf power or microwave power. (C) 1995 American Vacuum Society.