Novel pseudomorphic high electron mobility transistor structures with GaAs-In0.3Ga0.7As thin strained superlattice active layers

Abstract

The thin strained superlattice (TSSL) concept is introduced as a means for extending the practical range of application for pseudomorphic In_x Ga_1−x As on GaAs. Growth and characterization results are presented for pseudomorphic high electron mobility transistor structures with GaAs‐In_0.3 Ga_0.7 As TSSL active layers grown by molecular beam epitaxy. The TSSLs are composed of three periods of GaAs(15 Å)‐ In_0.3 Ga_0.7 As(h₂ ), where h₂ ranges from 30 to 52 Å. Modulation doping of the TSSLs is provided by atomic planar‐doped Al_0.3 Ga_0.7 As overlayers with 45 Å undoped spacers. 77 K Hall effect and transmission electron microscopy reveal that relatively thick TSSLs can be grown with high electronic and structural quality, comparable to much thinner In_0.3 Ga_0.7 As single quantum wells. Results are compared with a model for critical layer thickness and discussed in light of in situ reflection high‐energy electron diffraction measurements.