InGaAs channel MOSFET with self‐aligned source/drain MBE regrowth technology

Abstract

Abstract InGaAs is a promising alternative channel material to Si for sub‐22 nm node technology because of its low electron effective mass ( m * ) hence high electron velocities. We report a gate‐first MOSFET process with self‐aligned source/drain formation using non‐selective MBE re‐growth, suitable for realizing high performance scaled III‐V MOSFETs. A W/Cr/SiO 2 gate stack was defined on thin (4 nm/2.5 nm) InGaAs/InP channel by an alternating selective dry etch technique. A 5 nm Al 2 O 3 layer was used as gate dielectric. An InAlAs bottom barrier provided vertical confinement of the channel. An in‐situ H cleaning of the wafer leaves an epi‐ready surface suitable for MBE or MOCVD regrowth. Source/Drain region were defined by non‐selective MBE regrowth and in situ molybdenum contacts. First generation of devices fabricated using this process showed extremely low drive current of 2 μA/μm. The drive current was limited by an extremely high source resistance. A regrowth gap between source/drain and gate was the cause for high source resistance. The gap in the regrowth was because of low growth temperature (400 °C). A modified high temperature growth technique resolved the problem. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)