SiC for High Power Electro-Optic Switching Application.
Abstract
Photoconductive semiconductor switches have unique advantages such as high power, speed, negligible time jitter and long lifetime. Silicon carbide (SiC), due to its high dielectric strength and other desired properties, is an excellent material for photoconductive switches. However, no appreciable result has been reported on cubic silicon carbide (3C-SiC) photoconductive switches. In this research, photoconductive switches were fabricated on the following three types of 3C-SiC substrates: (i) boron doped, (ii) unintentionally doped single crystals and (iii) polycrystalline 3C-SiC. The switches were investigated using ArF and XeCl excimer lasers. Practical switches with many potential applications were successfully fabricated. The best results were obtained from the switches made from the polycrystalline material. The dark resistivity of the material was about 10(exp 6) ohms cm. The operating breakdown field was 2.5 x 10(exp 5) V/cm, which is the highest reported for all lateral geometry photoconductive switches, and was limited by the surface flashover effects. The highest peak photocurrent density through the switches was about 10 kA/sq cm. The ratio of the off-state resistance to the on-state resistance (Roff/Ron) was approx. 10(exp 5), and the lowest on-state resistance was 45 ohms. The width of the photocurrent pulse was 15 to 30 ns which was limited by the laser pulse, indicating that the switches can operate in the megahertz range.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1996
- Accession Number
- ADA313853
Entities
People
- Michael G. Spencer
- Senpeng Sheng
Organizations
- Howard University