Study and Application of Reactive Ion Etching on Pseudomorphic InGaP/InGaAs/InGaP HEMTs

• Main Authors: Chin, C.Y., 秦啟元
• Other Authors: Su, Y.K.
• Format: Others
• Language: en_US
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/77489188708794666041

碩士 === 國立成功大學 === 電機工程研究所 === 85 === 　　A highly selective reactive ion etching (RIE) process based on BCl3/Ar plasma was applied as a gate-recess technique in fabrication of InGaP/InGaAs/InGaP PHEMT. In our study, we systematically changed the mixing ratio between BCl3 and Ar gases and investigated its influence on etching selectivity between InGaP and GaAs materials. Atomic force microscopy (AFM), photoreflectance (PR), and Raman scattering (RS) were applied to determine the surface roughness of InGaP/InGaAs/InGaP HEMT caused from the BCl3/Ar plasma bombardment. It was found that sample dry etched with a 6 seem BCl3 flow rate, a 4 seem Ar flow rate, and a 100 W RF power has the smallest amount of damage. The results of RS and PR spectra were consistent with those evaluated by AFM. By using the optimum condition for the later-on gate recess, we have successfully fabricated the InGaP/InGaAs/InGaP PHEMT. The DC and microwave characteristics of device fabricated by this optimum condition were superior to the wet etched device and the other dry etched device. Microwave measurements of this dry etched device with 0.8 μm gate length revealed cut off frequency fT of 20 GHz and fmax of 54 GHz.