Title :
Development of techniques to monitor and control minority carrier lifetime in silicon to improve yields in a university fab
Author :
Will, James A., II ; Capasso, Keith ; Jackson, Michael A.
Author_Institution :
Dept. of Microelectron. Eng., Rochester Inst. of Technol., NY, USA
Abstract :
Measurement of minority carrier lifetime (τ), either indirectly via pn diode leakage current or directly from MOS capacitors, is used as a monitor to detect and correct contamination in an university fab. Diodes fabricated utilizing an internal gettering process exhibited improvements in leakage current levels about the wafer center when compared with diodes fabricated sans gettering, indicating the possibility of contamination by outdiffusion of impurities from the tube walls. Surface charge analysis (SCA) of an oxidized silicon wafer detected a 30% decrease in τ over a 6 hr N2 anneal in the tube used for gettering. The same experiment conducted in a tube contaminated with Zn yielded a 45% drop in lifetime. Both gas sources and RCA clean chemistry are being investigated as possible contamination sources of the getter tube
Keywords :
MOS capacitors; carrier lifetime; elemental semiconductors; getters; integrated circuit yield; leakage currents; minority carriers; silicon; surface charging; surface cleaning; 6 h; MOS capacitors; N2; RCA clean chemistry; Si; contamination; diode leakage current; gas sources; internal gettering process; minority carrier lifetime; outdiffusion; surface charge analysis; university fab; yields; Charge carrier lifetime; Contamination; Current measurement; Diodes; Gettering; Leak detection; Leakage current; MOS capacitors; Monitoring; Pollution measurement;
Conference_Titel :
University/Government/Industry Microelectronics Symposium, 1997., Proceedings of the Twelfth Biennial
Conference_Location :
Rochester, NY
Print_ISBN :
0-7803-3790-5
DOI :
10.1109/UGIM.1997.616681