Selective CaAs／AlGaAs RIE Etching Using SIC<sub>4</sub>／CF<sub>4</sub>／He Gas Mixture

1ntroduction Disc∬鵡low noisc AIGaAs1GaAs HEMT(High El㏄tmn Mob皿ity Transistof)has b㏄n usedextensively fbr DBS oonverter systems．To minimize the size and reduce the pro(1uction cost of the DBS converter for next gcneration systems，MMIC(Monolithic Micmwave Inte餌ted Circuit)t㏄hnology is mandatory andthehighlyun届omHEMTch蹴肥血ticsinaw価er and wafer to wafer is indispensable for MMIC fabdcadon輌山high yiel．d． It is generally known山at a gate-1℃cess process is oneofthek￠yissuesforachievingahighlyunifom HEMT ch紅acteristics．A dry gate-rccess pr㏄oss，in which the sel㏄tivity in etching rate for GaAs and for AIGaAs is high，主s very useful to improve the unifomity and the rep roducibility ohhe HEMTs． GaAs1AIGaAs se1㏄dve etching was f智st developed by H娠・s泳aeI訓・usingCC12Fμegassys陀m(1)・and adapted to gate-recess process of n＋一GaAs capPe〔1 AIGaAs！GaAs HEMT gate-recess process， Howcvcr・CCl2F2・a kind of nuor㏄飢bon・is being regula肥d賦》use，as k is one of the ga6es that des汀oy 由eO31ayerats㈲sphere・Wehave血vcl・卸anew ctchinggassystcmwhi・chcanakem蹴thcCC』F2 systemめperfom1GaAs1AIGaAsselec亘vee敦ohing・The 総謡、縮離飾溜㎝4温em xtu「e s Wc rcport here abouUhc etching mechanism and RIE induced damag￠for山e fluor㏄arbon-f鵬selec廿ve etching system using Auger Spectroscopy and the Scho蜘(Hode characte一、sdcs． Dry etching with the gas system of SiCl4／CF4！He mixtu爬was perfomed with a conv￠ntiona1parallel plaむe鶴actof system，in which血e lowcr elec廿ode was covere恩with a quartz plate．To achieve a less-damage dry re㏄ss pr㏄ess，the RF power of a Reactive Ion