Title :
Undoped SiGe heterostructure field effect transistors
Author :
Jackson, Thomas N. ; Nelson, Shelby F. ; Chu, J.O. ; Meyerson, B.S.
Author_Institution :
IBM T.J. Watson Res. Center, Yorktown Heights, NY
fDate :
11/1/1993 12:00:00 AM
Abstract :
Summary form only given. Undoped SiGe heterostructure MISFETs which are an analog of III-V HIGFETs and use a biaxially strained Si channel with a SiGe gate insulator are reported. The devices were grown on a buffer layer of relaxed SiGe, as were previously reported SiGe modulation-doped heterostructure FETs, but here no doping is used; instead, a gate field is used to form the electron channel. Undoped Si/SiGe heterostructure MISFETs show good FET characteristics with low gate leakage at 77 K. FETs with 1.5-μm-gate-length and SiGe insulator thickness of 100 nm have a maximum transconductance greater than 100 mS/mm at 77 K. By reducing the insulator thickness to 50 nm, a maximum transconductance greater than 150 mS/mm was obtained for a 2. 5-μm-gate-length device. A field effect mobility at 77 K of 16500 cm 2/V-s, extracted from long gate-length device data, is comparable to that of modulation-doped high-mobility samples
Keywords :
Ge-Si alloys; carrier mobility; insulated gate field effect transistors; leakage currents; semiconductor materials; 1.5 micron; 100 mS/mm; 100 nm; 150 mS/mm; 2.5 micron; 50 nm; 77 K; Si-SiGe; SiGe gate insulator; biaxially strained Si channel; buffer layer; electron channel; field effect mobility; field effect transistors; gate field; gate length; insulator thickness; long gate-length device data; low gate leakage; relaxed SiGe; transconductance; undoped SiGe heterostructure MISFET; Epitaxial layers; FETs; Germanium silicon alloys; HEMTs; III-V semiconductor materials; Insulation; MISFETs; MODFETs; Silicon germanium; Transconductance;
Journal_Title :
Electron Devices, IEEE Transactions on
