ORIGIN OF VOID DEFECTS IN HG1-XCDXTE GROWN BY MOLECULAR-BEAM EPITAXY

Characterization of defects in Hg-1-x CdxTe compound semiconductor is essential to reduce intrinsic and the growth-induced extended defects which adversely affect the performance of devices fabricated in this m aterial system. It is shown here that particulates at the substrate su rface act as sites where void defects nucleate during Hg-1-x CdxTe epi taxial growth by molecular beam epitaxy. In this study, we have invest igated the effect of substrate surface preparation on formation of voi d defects and established a one-to-one correlation. A wafer cleaning p rocedure was developed to reduce the density of such defects to values below 200 cm(-2). Focal plane arrays fabricated on low void density m aterials grown using this new substrate etching and cleaning procedure were found to have pixel operability above 98.0%.