Patent ID: 6635404
Filing Date: 2003-10-21
Classification: H01L

Abstract:
A method of fabricating a gamma gate of a high-speed and low-noise HEMT comprising the steps of:depositing a first resist layer on a GaAs substrate; forming a first resist pattern on the GaAs substrate by exposing, developing and baking the first resist layer, sequentially; depositing a second resist layer on the first resist pattern and the first resist layer; forming a second resist pattern so that a marginal portion of the second resist pattern overlaps the first resist pattern, by exposing, developing the second resist pattern at a negative slope of 89Â° or less, and baking the second resist layer, sequentially; etching the GaAs substrate using the first and second resist layers as a mask to form a recess on the GaAs substrate; depositing a metal layer on the resultant structure; and removing the first and second resist layers to form the gamma gate with a head and a footprint, wherein the footprint of the gamma gate is formed in the marginal portion of the second resist pattern overlapping the first resist pattern and the width of the overlapped portion defines the size of the footprint of the gamma gate, and wherein the head of the gamma gate is formed on the first resist layer in a residual portion of the second resist pattern other than the overlapped portion.