P A P E R    T I T L E
Manufacturable In0.8Ga0.2P/In0.53Ga0.47As/InP Doped-channel HFETs with fT and fmax over 170 GHz

A U T H O R  /  C R E D I T S
Z. Tang, H. Hsia, H. C. Kuo, D. Caruth, G. E. Stillman, and M. Feng
Microelectronics Laboratory, Department of Electrical and Computer Engineering
University of Illinois at Urbana-Champaign, Urbana, IL 61801-2355
Phone: (217)333-4054, e-mail: ztang@hsic.ccsm.uiuc.edu

A B S T R A C T
We demonstrate the fabrication and performance of 0.15 mm T-gate high-speed In0.8Ga0.2P/In0.53Ga0.47As/InP doped-channel HFETs with non-alloyed ohmic contacts. A high peak trans-conductance of 718 mS/mm and a high maximum current density of 890 mA/mm were achieved. The ohmic contact was fabricated by using AuGe/Ni/Au deposited on highly doped InGaAs contact layer without high temperature alloy. The on-resistance of 1.2 WŚmm was measured. The high doping InGaAs channel leads to excellent RF performance: ft of 171 GHz and fmax of 186 GHz at Vds = 1.5 V. These are the best results ever reported for doped-channel HFETs, which is comparable to other HFETs and HEMTs with same gate length. This result suggested that In0.8Ga0.2P/In0.53Ga0.47As/InP doped-channel HFET is suitable for high-speed and high-power device application.