Gate Length Dependence of Large-Signal Output Characteristics for the MOSFETs in the Breakdown Region Using X-Parameter Model

Abstract

In this letter, the gate length dependence of $\text{X}^{S}_{2121}$ and $\text{X}^{T}_{2121}$ intercept behaviors for the MOSFETs in the breakdown region is first analyzed using the X-parameter model. Shorter gate length decreases $\text{X}^{S}_{2121}$ coefficients and increases $\text{X}^{T}_{2121}$ coefficients at high drain voltage and high input power due to the significant RF avalanche effect in the high field region. $\text{X}^{S}_{2121}$ and $\text{X}^{T}_{2121}$ coefficients are determined using artificial neural network. Good agreement between the measured and fitted output scattering wave is achieved. The presented analysis for the gate length dependence $\text{X}^{S}_{2121}$ and $\text{X}^{T}_{2121}$ can be beneficial to CMOS power amplifier designs with the scaled-down MOSFETs.