COMPOUND SEMICONDUCTOR DEVICE

摘要

PURPOSE:To enable to set at the desired optimum value the thickness and carrier density of a channel layer which determines the element characteristic of a Hall element, a Schottky gate FET, etc. by a method wherein a layer of high impurity density corresponding to the amount of surface charges forming surface levels is formed in the neighborhood of the surface of a III-V group compound such as GaAs. CONSTITUTION:An N type GaAs channel layer 2 is formed on a semi-insulating GaAs substrate 1 by doping an impurity such as Si or Sn by vapor growing method. The carrier density and the thickness of the channel layer are contrived to become 1X10<17>cm<-3> and 0.2mum respectively. An N type GaAs layer 4 of further higher impurity density is formed at the surface region on this N type GaAs channel layer 2. Either continuous formation or isolated formation at some intervals is available. The product (so-called nd product) of the carrier density and the thickness of this high density layer 4 is so controlled as to be coincident with the density of the surface levels of a GaAs semiconductor device.