Both reversible and irreversible resistance switchings have been investigated in boron-and arsenic-doped LPCVD polycrystalline silicon film resistors. The effects of film thickness and doping concentration on the transition voltage and current have been characterized for different length resistors having film thickness from 0.1 to 1.2 t~m and doping concentration ranging from 5 • 10 TM to 1 • 10 z~ cm-3. Under a large voltage bias, the resistor can be switched to a conductive "on" state or to a "short" state having resistance reduction by a factor of 103-106, or it can be blown "open". The transition voltage and current and the resistance after switching depend strongly on film thickness, doping concentration, and applied power. A simple qualitative model is proposed to explain these resistance switching phenomena.

A new programming technique for polysilicon resistor fuses using low input electrical power has been demonstrated. In contrast to the conventional technique which programs fuses in the air at atmospheric pressure, the new technique is to program fuses in a low-pressure gas ambient. Removal of the entire passivation layers over the fuses is not necessary thus avoiding the contamination problem.

A novel reliability simulator and its associated circuitlevel degradation models with automated parameter extraction procedures for VLSI circuits have been developed. This circuit reliability modeling and simulation environment can serve as a bridge between the system and device reliability. Performance and lifetime of digital and analog ICs can be optimized through the usage of this reliability simulator.

The sensitivity analysis results are of fundamental importance to the VLSI design because it provides the information to identify a set of critical parameters for each fabrication technology. We have formulated a new sensitivity function to select the critical MOS parameters for digital and analog circuit designs using various MOSIS fabrication technologies. The most sensitive parameters with respect to the drain current have been found to be the gate-oxide thickness, threshold voltage, mobility, and body-effect coefficient. As for the transistor output conductance, the channel-length modulation coefficient and saturated carrier velocity are the most sensitive parameters in addition to those parameters mentioned above. The set of critical parameters plays an important role in the statistical circuit analysis where the worst/best-case parameter files have to be established and in the extreme-temperature circuit simulation.

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