STUDY OF MICRODEFECTS FORMING AT DIFFERENT INTRINSIC GETTER GENERATION STAGES IN CZ-Si
Microdefects forming at different intrinsic getter generation stages in (001) CZ-Si have been studied using X-ray diffuse scattering (XRDS) method and selective etching. We show that if the intrinsic getter forms in the deplete layer forming due to the high-temperature heat treatment, the wafer edge has a threshold oxygen concentration region (approx. (5-6) 1017 cm3) below which the microdefects cannot be detected by etching. XRDS proves the very low concentration of the microdefects in this region. After the gettering heat treatment, wafer bulk regions with different oxygen concentration levels (wafer center and edge) XRDS detects interstitial plate-shaped microdefects presumably located in the {110} planes and producing nonspherical displacement fields. The XRDS pattern suggests that vacancy-type microdefects are also present. Selective chemical etching with modified chromium etcher also detects two types of microdefects in the wafer bulk. Combined use of etching and XRDS is an effective tool for the structural diagnostics of silicon wafers with intrinsic getter and gettering efficiency assessment