High RF burnout resistance silicon Schottky barrier mixer diodes

Abstract

Summary form only given: Microwave Schottky mixer and detector diodes have been utilized in Microwave Systems. In general, thermal compression bonded Schottky diodes exhibit superior noise figure and better mechanical and environmental reliability when compared to point-contact diodes. However, Schottky diodes have been proven less resistant to burnout in radar systems. Short, high-power RF pulses (T = 1-50 nsec) such as those occuring with T-R tubes are detrimental to the Schottky diodes. This paper describes the investigation of high burnout resistant Schottky barrier diodes for X and Ku-band frequencies. High burnout resistant Schottky barrier diodes have been developed by utilizing Platinum for the barrier on n-type epitaxial silicon. The epitaxial Silicon parameters and metalization schemes were optimized to obtain low noise figure and high burnout resistance. X-band diodes exhibit RF burnout greater than 100watts (T= 3 nsec, 103 pulses per sec) and r:burnout of 3 watts which is two to five times greater than presently manufactured Schottky diodes. The na no second pulse burnout exceeds even that of the high point-contact diodes. Similar results were noticed for Ku-band diodes. These diodes exhibit near ideal electrical characteristics and low noise figure. The processing and characteristics of such a Schottky barrier for mixer and detector applications will be discussed. Reflected RF power was monitored during the RF burnout tests and SEM pictures were taken at various stages to understand the burnout mechanism. A complete failure analysis of these devices will be presented.