Patent ID: 6139995
Filing Date: 2000-10-31
Classification: G03F,H01L

Abstract:
A method for the manufacture of a Schottky gate transistor comprising the steps of:forming a source and drain in a III-V semiconductor substrate, andforming a Schottky gate on the surface of said III-V semiconductor between said source and drainthe invention characterized in that said Schottky gate is formed by the steps comprising:a. depositing a first level of photoresist on the surface of said substrate, said first level of photoresist having a thickness t.sub.1,b. exposing said first level of photoresist with a first photomask with a first photolithographic pattern having a rectangular shape with width w.sub.1 and length l.sub.1, with the length dimension extending along the direction separating the source and drain, said first photolithographic pattern further having at a first set of alignment marks, thereby forming a latent image of said first set of alignment marks in said first level of photoresist,c. depositing a second level of photoresist on said first level of photoresist, said second level of photoresist having a thickness t.sub.2,d. aligning a second photomask to said substrate by registering a second set of alignment marks on said second photomask with said latent image of said first set of alignment marks,e. exposing said second level of photoresist with a pattern having a rectangular shape with width w.sub.2 and length l.sub.2, and further where length l.sub.2 is greater than length l.sub.1,f. developing said first and second levels of photoresist to form a T-shaped feature,g. depositing a metal layer to fill a portion of said T-shaped feature, said metal layer having a thickness h.sub.1 +h.sub.2, where h.sub.1 is essentially equal to t.sub.1 and h.sub.2 is substantially less than t.sub.2, andh. dissolving away said first and second level of photoresist leaving a T-shaped Schottky gate.