SOLID STATE BROADBAND OPTICAL DETECTOR.

A fast response, sensitive, broadband light demodulator was developed. The demodulator is a silicon photodiode designed to be operated in the avalanche breakdown region to achieve improved sensitivity due to photocurrent multiplication. The program was divided into two tasks Task I, development and fabrication of the demodulators and Task II, the testing and characterization. The avalanche photodiodes have an NP pi P structure and are fabricated on epitaxial material using standard planar techniques. Calculations of the required impurity concentrations and the fabrication results are given. The studies to eliminate microplasmas are discussed. Microplasmas are small areas of localized breakdown that prevent high uniform gain. The results of the measurements on quantum efficiency, avalanche gain characteristics, noise performance, and microwave frequency response are discussed. Results show the diodes have gains of over 100, a flat frequency response out to 1 GHz, and an N.E.P. of less than 10 to the minus 12 WHz12. Author