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Identification of defects in SOI (silicon-on-insulator) wafers

Conference ·
OSTI ID:7008008

Defects and metal contamination in device areas of silicon integrated circuits (IC) can limit yield in IC fabrication. We describe an electrochemical method for identification of structural defects and metal contamination in low-doped n-type silicon (dopant concentration of about 10{sup 15}/cm{sup 3}). Anodic etching in 5 wt % hydrofluoric acid produces crystallographic etch pits which correlate with both structural and impurity defects. Etch pit densities also correlate well with reported values of defect densities calculated from gate oxide breakdown. We show that the method is particularly suited to defect delineation in thin-film silicon-on-insulator (SOI) wafers. The technique is superior to chemical decoration etches and to transmission electron microscopy for defect delineation in thin-film SOI wafers since it does not etch bulk silicon and it has a detection limit much lower than 10{sup 4}--10{sup 5} defects/cm{sup 2}. We used the procedure to demonstrate how defect levels are strongly affected by the process parameters used to synthesize Zone Melt Recrystallization (ZMR) and Separation by IMplanted OXygen (SIMOX) wafers. 10 refs., 6 figs.

Research Organization:
Sandia National Labs., Albuquerque, NM (USA)
Sponsoring Organization:
DOE/DP
DOE Contract Number:
AC04-76DP00789
OSTI ID:
7008008
Report Number(s):
SAND-89-2696C; CONF-900598--1; ON: DE90006020
Country of Publication:
United States
Language:
English