| 초록 |
Dry etching of undoped, n- and p-type GaN films was carried out in Cl2-based inductively coupled plasmas using different rf excitation frequencies of 100 kHz and 13.56 MHz, in which the rf chuck power source operates. The etch rates with lower frequency of 100 kHz are somewhat greater than those with higher frequency of 13.56 MHz due to higher ion bombarding energy with lower frequency. The highest etch rates with the 100 kHz frequency were obtained at moderately high ICP power of 700 W: ~ 9300 /min of n-GaN, ~ 5300 /min of p-GaN and ~ 7100 /min of undoped GaN. The 13.56 MHz frequency of rf chuck power source produced maximum etch rates of ~ 7900 /min of n-GaN, ~ 5800 /min of p-GaN and 6100 /min of undoped GaN at 20 mTorr, 700 W ICP and 150 W rf power. The surface roughness showed quite smooth morphology (rms 1.1 1.3 nm).
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