The Effect of Processing Parameters on the Lifetime of ( Hg , Cd ) Te Material

Abstract

The lifetime of n‐type material in the 3–5 μm wavelength range was investigated. The lifetime of wafers was determined by the photoconductive decay technique with a pulsed laser and the measurement was repeated after various processing steps. The lifetime for a lapped surface was as low as 0.2 μsec and was found to have improved 4.5 μsec after the surface damage was removed by chemical etching. The depth of the damage was determined by x‐ray rocking curves. For a surface lapped with a 1 μm grit size, the damage depth was found to be 20 μm. Multiple element detector arrays were fabricated and the lifetime of the finished were measured and found to be 2.5 μsec. These measurements indicated that those various processing steps used for the device fabrication did not degrade the lifetime significantly.