Patent ID: 6049097
Filing Date: 2000-04-11
Classification: H01L

Abstract:
A field effect type semiconductor device comprising:a first semiconductor layer having a first electron affinity .chi..sub.1 ;a second semiconductor layer formed on said first semiconductor layer, said second semiconductor being undoped and having a second electron affinity .chi..sub.2 smaller than said first electron affinity;a third semiconductor layer formed on said second semiconductor layer, said third semiconductor layer having a donor impurity concentration and having a third electron affinity .chi..sub.3 smaller than said first electron affinity .chi..sub.1 and larger than said second electron affinity .chi..sub.2,said first and third semiconductor layers including indium, a percentage composition of indium in said first semiconductor layer being larger than a percentage composition of indium in said third semiconductor layer;a fourth semiconductor layer formed on said third semiconductor layer, said fourth semiconductor layer being undoped and having a fourth electron affinity .chi..sub.4 smaller than said third electron affinity .chi..sub.3 ;a control electrode formed on said fourth semiconductor layer; andfirst and second ohmic electrodes formed on said fourth semiconductor layer and sandwiching said control electrode, a voltage at said control electrode changing an amount of charges of an electron channel formed in said first semiconductor layer, to control a current flowing between said first and second electrodes.