NONCONTACT MINORITY-CARRIER LIFETIME MEASUREMENT OF SI AND SIGE EPILAYERS PREPARED BY ULTRAHIGH-VACUUM ELECTRON-CYCLOTRON-RESONANCE CHEMICAL-VAPOR-DEPOSITION

A 70 MHz inductively coupled rf bridge probe is used to measure the mi nority carrier lifetime of the Si and SiGe epilayers grown by ultrahig h vacuum electron cyclotron resonance chemical vapor deposition (UHV-E CRCVD) at temperatures below 560 degrees C. Proper surface treatments before HF immersion are required for the accurate measurement of the b ulk minority carrier lifetime. The effects of the process parameters s uch as the substrate de bias, the distance of the ECR layer from the s ubstrate, and the substrate temperature, including in situ surface cle aning, on the minority carrier lifetime of the Si and SiGe epilayers a re examined by the rf bridge probe. It is confirmed that the rf bridge probe can monitor the epitaxial quality of low temperature Si and SiG e epilayers, making it an indispensable tool for the high quality devi ce fabrication with Si and SiGe epitaxial layers grown by low temperat ure UHV-ECRCVD. (C) 1996 American Vacuum Society.