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Vol.59, No.2, 121 ~ 127, 2021
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| Title |
| Fluorine-based Inductively Coupled Plasma Etching of α-Ga2O3 Epitaxy Film |
| Ji Hun Um , Byoung Su Choi , Woo Sik Jang , Sungu Hwang , Dae-woo Jeon , Jin Kon Kim , Hyun Cho |
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| Abstract |
| α-Ga2O3 has the largest bandgap (~5.3 eV) among the five polymorphs of Ga2O3 and is a promising candidate for high power electronic and optoelectronic devices. To fabricate various device structures, it is important to establish an effective dry etch process which can provide practical etch rate, smooth surface morphology and low ion-induced damage. Here, the etch characteristics of α-Ga2O3 epitaxy film were examined in two fluorine-based (CF4/Ar and SF6/Ar) inductively coupled plasmas. Under the same source power, rf chuck power and process pressure, an Ar-rich composition of CF4/Ar and an SF6-rich composition of SF6/Ar produced the highest etch rates. Monotonic increase in the etch rate was observed as the source power and rf chuck power increased in the 2CF4/13Ar discharges, and a maximum etch rate of ~855 A/min was obtained at a 500 W source power, 250 W rf chuck power, and 2 mTorr pressure. A smooth surface morphology with normalized roughness of less than ~1.38 was achieved in the 2CF4/13Ar and 13SF6/2Ar discharges under most of the conditions examined. The features etched into the α-Ga2O3 layer using a 2CF4/ 13Ar discharge with 2 mTorr pressure showed good anisotropy with a vertical sidewall profile.
(Received December 15, 2020; Accepted January 14, 2021) |
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| Key Words |
| α-Ga2O3 epitaxy film, SF6, Ar, CF4, Ar, inductively coupled plasma, etch characteristics |
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