ABSTRACT
In this chapter, the authors investigate the nature of oxide breakdown and stress-related degradation mechanisms in MOS transistors. Gate-oxide breakdown leads to a catastrophic and permanent failure in MOS devices. The breakdown is accompanied by a sudden discontinuous increase in the oxide conductance and the gate current noise. Breakdown is a gradually increasing phenomenon and realized by defects such as electron traps in the oxide structure. Consequently, the drain current, channel resistance, and transconductance gain of MOS transistor decrease and degrade performance of RF circuits, such as oscillators. First, one needs to choose larger gm-devices to compensate the oscillator loop gain reduction due to HC. The exponential-law and defect-generation models quantified the MOS breakdown lifetime versus the oxide-thickness, gate area, temperature, gate voltage, and cumulative failure rate.
