Formation of Thin InAs Films for Electronic Devices

Abstract

The formation of InAs thin films by the coevaporation technique consists of converting initially deposited In droplets into InAs crystallites. The size and the perfection of the crystallites determine the electrical properties of the films. These parameters then can be controlled by the evaporation procedures. Films deposited at a substrate temperature ≥600 °C with a deposition rate ≥1500 A/min are coarse crystalline (diam ≤0.5 mm) and exhibit a Hall mobility of ≥10 000 cm2/Vsec and a carrier concentration of ≥1×1016/cm3. Films deposited at a substrate temperature ≤400 °C and a deposition rate ≤100 A/min consist of very small crystallites (diam ≤500 A) and exhibit a Hall mobility ≤100 cm2/Vsec and a carrier concentration ≥1×1018/cm3. Any desired mobility, carrier concentration, or surface smoothness (as determined by crystallite size) or combination of these properties can be made by varying substrate temperature and/or deposition rate. InAs films with a reasonably smooth surface and a Hall mobility of 20...