Method of manufacturing a self-aligned GaAs MESFET with T type tungsten gate

Claim 1

A method of manufacturing a self-aligned MESFET with T type gate electrode of the tungsten comprising the processes of: depositing a silicon (Si) thin film onto entire surface of a semi-insulating GaAs substrate by PECVD(plasma enhanced chemical vapor deposition), depositing a Si 3 N 4 film onto the silicon (Si) thin film by PCVD (photo chemical vapor deposition), and ion implanting for a n active layer using a photoresist as a mask; forming a gate electrode pattern by etching said Si 3 N 4 film using a photoresist as a mask to form the gate electrode; growing the tungsten by selective chemical vapor deposition only onto the exposed Si thin film in order not to deposit the tungsten onto said Si 3 N 4 film; growing the tungsten film transversely for forming a tungsten gate electrode with T type; forming a n+ layer by ion implantation so that the gap between said gate electrode and said n+ layer is 1000 Å through 2000 Å using said T type tungsten gate; activating said n and n+ layer using said Si thin film and Si 3 N 4 film as a capping film; ion implanting for said n and n+ active layers and for isolation between devices through said Si thin film and Si 3 N 4 film; etching said Si thin film and Si 3 N 4 film and depositing an ohmic metal (AuGe/Ni) by a lift-off technique using a photoresist as a mask to form a source and a drain.

Claim 2

A method of manufacturing a self-aligned MESFET with T type gate electrode of the tungsten comprising the processes of: depositing a silicon (Si) thin film onto entire surface of a semi-insulating GaAs substrate by PECVD(plasma enhanced chemical vapor deposition), depositing a Si 3 N 4 film onto the silicon (Si) thin film by PCVD (photo chemical vapor deposition), and ion implanting for a n active layer using a photoresist as a mask; forming a gate electrode pattern by etching said Si 3 N 4 film using a photoresist as a mask to form the gate electrode; growing the tungsten by selective chemical vapor deposition only onto the exposed Si thin film in order not to deposit the tungsten onto said Si 3 N 4 film; growing the tungsten film transversely for forming a tungsten gate electrode with T type; forming a n+ layer by ion implantation so that the gap between said gate electrode and said n+ layer is 1000 Å through 2000 Å using said T type tungsten gate; activating said n and n+ layer using said Si thin film and Si 3 N 4 film as a capping film; ion implanting for said n and n+ active layers and for isolation between devices through said Si thin film and Si 3 N 4 film; etching said Si thin film and Si 3 N 4 film and depositing an ohmic metal (AuGe/Ni) by a lift-off technique using a photoresist as a mask to form a source and a drain.