Method for producing a metal semiconductor field effect transistor

Claim 1

A method for producing a metal semiconductor field effect transistor comprising the steps of: depositing a film layer of silicon nitride with a thickness of approximately 1000 Å on the upper surface of a semiconductor substrate of GaAs; forming a first mask pattern wherein the mask is made of a material selected from the group consisting of SiO 2 , Ti, W, Mo, or Ni on one portion of the upper surface of the film layer of silicon nitride; forming a first layer which will be a buffer layer of Al x Ga.sub.(1-x) As in a predetermined region of the semiconductor substrate using said first mask pattern by selective Al ion implantation at a dose of 8×10 16 cm -2 and an acceleration energy of 30 keV; forming a second layer which will become an active layer of GaAs in a predetermined region of the semiconductor substrate using said first mask pattern by selective ion implantation at a dose of 8×10 12 cm -2 and an acceleration energy of 60 keV; removing said first mask pattern; removing said film layer of silicon nitride, forming a metal gate electrode on the upper surface of the semiconductor substrate, the metal being of a material which when connected to GaAs forms a Schottky contact, forming a second mask pattern wherein the mask is made of a material selected from the group consisting of SiO 2 , Ti, W, Mo, or Ni on one portion of the upper surface of a semiconductor substrate of GaAs; forming regions of high impurity concentration regions in predetermined regions at both sides of said gate electrode in the semiconductor substrate using said second mask pattern by ion implantation at a dose of 4×10 13 cm -2 and an acceleration energy of 150 keV; removing the second mask pattern; annealing the semiconductor substrate comprising said first and second layers and said regions in N 2 gas at 800° C. for 20 minutes, wherein said first and said second layers become a buffer layer of Al x Ga.sub.(1-x) As and an active layer of GaAs, respectively, and said regions become high impurity concentration regions; and forming a source electrode and a drain electrode on the upper surface of said high impurity concentration regions, respectively, whereby said buffer layer of Al x Ga.sub.(1-x) As is formed above the active layer of GaAs.

Claim 2

A method for producing a metal semiconductor field effect transistor comprising the steps of: depositing a film layer of silicon nitride with a thickness of approximately 1000 Å on the upper surface of a semiconductor substrate of GaAs; forming a first mask pattern wherein the mask is made of a material selected from the group consisting of SiO 2 , Ti, W, Mo, or Ni on one portion of the upper surface of the film layer of silicon nitride; forming a first layer which will be a buffer layer of Al x Ga.sub.(1-x) As in a predetermined region of the semiconductor substrate using said first mask pattern by selective Al ion implantation at a dose of 8×10 16 cm -2 and an acceleration energy of 30 keV; forming a second layer which will become an active layer of GaAs in a predetermined region of the semiconductor substrate using said first mask pattern by selective ion implantation at a dose of 8×10 12 cm -2 and an acceleration energy of 60 keV; removing said first mask pattern; removing said film layer of silicon nitride, forming a metal gate electrode on the upper surface of the semiconductor substrate, the metal being of a material which when connected to GaAs forms a Schottky contact, forming a second mask pattern wherein the mask is made of a material selected from the group consisting of SiO 2 , Ti, W, Mo, or Ni on one portion of the upper surface of a semiconductor substrate of GaAs; forming regions of high impurity concentration regions in predetermined regions at both sides of said gate electrode in the semiconductor substrate using said second mask pattern by ion implantation at a dose of 4×10 13 cm -2 and an acceleration energy of 150 keV; removing the second mask pattern; annealing the semiconductor substrate comprising said first and second layers and said regions in N 2 gas at 800° C. for 20 minutes, wherein said first and said second layers become a buffer layer of Al x Ga.sub.(1-x) As and an active layer of GaAs, respectively, and said regions become high impurity concentration regions; and forming a source electrode and a drain electrode on the upper surface of said high impurity concentration regions, respectively, whereby said buffer layer of Al x Ga.sub.(1-x) As is formed above the active layer of GaAs.