Bipolar NPN ICEO leakage due to PETEOS deposition

A chronic NPN Bipolar ICEO leakage failure mode on a BiCMOS (B+) process was revealed to be caused by marginality in the CMOS oxide spacer film deposition process. It has been shown that residual carbon in the PETEOS spacer oxide film generated defects at the collector/base interface. These defects prevented epitaxial growth of the base region. The defects and ICEO leakage were eliminated by modifying the process conditions during the termination of the PETEOS oxide deposition.