FIELD-EFFECT TRANSISTORS IN HG1-XCDXTE GROWN BY PHOTOASSISTED MOLECULAR-BEAM EPITAXY

The first demonstration of Hg1- xCdxTe metal-insulator-semiconductor field-effect transistors prepared using n-type layers grown by photoassisted molecular beam epitaxy is reported. These transistor structures were processed by means of a new low-temperature (<60°C) semiconductor device processing technology developed at North Carolina State University, and differ significantly from structures previously reported in that (1) a depletion region instead of a surface inversion layer is used as the principle for device operation, (2) larger x-value Hgt xCdxTe is employed as the active region of the device, and (3) the transistor structures are fabricated without the use of ion implantation and thermal annealing processing steps. In addition, the low-temperature processing technology is compatible with the future development of superlattice and multilayer device structures consisting of Hg-based alloys, in which mercury interdiffusion at heterointerfaces can significantly alter the material properties. Depletion and enhancement-mode operation have been observed and digital inverter circuits have been characterized at speeds of 1 MHz. © 1990, American Vacuum Society. All rights reserved.