Title :
A dielectric-defined process for the formation of T-gate field-effect transistors
Author :
Metze, G.M. ; Bass, J.F. ; Lee, T.T. ; Porter, D. ; Carlson, H.E. ; Laux, P.E.
Author_Institution :
COMSAT Lab., Clarksburg, MD, USA
Abstract :
A novel process for the fabrication of tee- or gamma-shaped gate structures is presented. This process was utilized to fabricate 0.25 mu m*60 mu m and 0.25 mu m*150 mu m T-gate MESFETs. From S-parameter data up to 40 GHz, extrapolated cutoff frequencies as high as 55-65 GHz were obtained. DC yields as high as 80% over 3-in wafers were obtained using this dielectric defined T-gate (DDTG) process. Step-stress measurements indicate device reliability comparable to the normal MESFET process. Relative to multilayer resist processing techniques usually used to form T-gates, it is believed that the DDTG process will substantially increase the yield, uniformity, and reliability of FET-like devices/circuits using T-gates with geometries at or below 0.25 mu m.<>
Keywords :
Schottky gate field effect transistors; semiconductor technology; solid-state microwave devices; 0.25 micron; 65 GHz; DC yields; MESFETs; S-parameter data; T-gate; cutoff frequencies; device reliability; dielectric-defined process; fabrication; field-effect transistors; gamma-shaped gate structures; Dielectrics; Dry etching; FETs; Fabrication; Gallium arsenide; MESFETs; Millimeter wave circuits; Millimeter wave technology; Millimeter wave transistors; Resists;
Journal_Title :
Microwave and Guided Wave Letters, IEEE
