Breakdown effects on MOS varactors and VCO's

Abstract

The gate oxide breakdown effects of deep sub-micron devices, which degrade the performance of MOS varactors that in turn degrade the performance of LC Voltage Controlled Oscillators (VCO's), are presented. On wafer 0.16 µm CMOS devices are stressed; experimental data are analyzed and used for analytical derivations and simulations to show that the breakdown has twofold effects on the performance of the VCO's. Firstly, the increased conductance of the varactor degrades its quality, which increases the phase noise of the VCO's. This also reduces the amplitude at the output of the oscillator. Secondly, the value of the capacitance of the MOS varactor reduces, which shifts the oscillation frequency of the VCO's.

Soft breakdown on deep sub-micrometer RF nMOSFET performance

“…Therefore, it is required to study the soft breakdown effects on deep sub-micrometer RF MOSFETs. Combined effects of hot carrier and soft breakdown on RF MOSFETs have been reported in [5], and effects of hard breakdown on RF devices and circuit performance have also been reported in [6], [7]. Compared with hard breakdown (HBD), SBD is more prevalent for oxide stress at lower voltages and thinner oxides [SI.…”