Patent ID: 8610173
Filing Date: 2013-12-17
Classification: H01L

Abstract:
1. A layered epitaxial structure for enhancement and depletion PHEMT devices, comprising: a superlattice and buffer layer; an undoped back-barrier layer formed on the superlattice and buffer layer and made of aluminium gallium arsenide (AlGaAs); a doped back delta doping layer formed on the back-barrier layer; an undoped back-spacer layer formed on the back delta doping layer and made of aluminium gallium arsenide (AlGaAs); an undoped channel layer formed on the back-spacer layer and made of indium gallium arsenide (InGaAs); an undoped spacer layer formed on the channel layer and made of aluminium gallium arsenide (AlGaAs); a delta doping layer formed on the spacer layer; an undoped enhancement barrier layer formed on the delta doping layer; a doped first etch stopper layer, formed on the enhancement barrier layer and made of aluminium arsenide (AlAs); a doped first depletion barrier layer formed on the first etch stopper layer; an undoped second depletion barrier layer formed on the first depletion barrier layer; a doped second etch stopper layer formed on the second depletion barrier layer and made of aluminium arsenide (AlAs); a first cap layer doped with n-type doping, formed on the second etch stopper layer and made of gallium arsenide (GaAs); an undoped second cap layer formed on the first cap layer and made of gallium arsenide (GaAs); a third etch stopper layer doped with n-type doping, formed on the second cap layer and made of aluminium arsenide (AlAs); and an ohmic layer doped with n-type doping, formed on the third etch stopper layer and made of gallium arsenide (GaAs).