OBIC analysis of stressed, thermally-isolated polysilicon resistors
- Sandia National Labs., Albuquerque, NM (United States)
- National Inst. of Standards and Technology, Gaithersburg, MD (United States)
- Maryland Univ., College Park, MD (United States)
High gain Optical Beam Induced Current (OBIC) imaging has been used for the first time to examine the internal structural effects of electrical stress on thermally-isolated polysilicon resistors. The resistors are examined over a wide range of current densities, producing Joule heating up to {approximately}1200{degrees}C. Throughout this current density range, the OBIC images indicate a clustering of dopant under dc stress and a more uniform distribution under ac conditions. The OBIC images also reveal areas that are precursors to catastrophic resistor failure. In addition to OBIC imaging, conventional electrical measurements were performed, examining the polysilicon resistance degradation and time-to-failure as a function of electrical stress. The electrical measurements show a monotonic increase in polysilicon resistor lifetime with frequency (up to 2 kHz) when subjected to a bipolar ac stress. The enhanced lifetime was observed even under high temperature (from Joule heating) stress conditions previously reported to be electromigration-free. The dopant redistribution indicated by the OBIC images is consistent with an electromigration stress experienced by the polysilicon resistors. The implications for thermally-isolated polysilicon resistor reliability are examined briefly.
- Research Organization:
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States); National Inst. of Standards and Technology, Gaithersburg, MD (United States)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 26615
- Report Number(s):
- SAND-94-2464C; CONF-950432-1; ON: DE95008511
- Resource Relation:
- Conference: International reliability physics symposium, Las Vegas, NV (United States), 3-6 Apr 1995; Other Information: PBD: [1994]
- Country of Publication:
- United States
- Language:
- English
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