Analysis and Compact Modeling of MOSFET High-Frequency Noise

We have developed a high-frequency noise model for short channel MOSFETs by considering the position dependent surface potential which results in a non-uniform mobility distribution along the channel. The chosen approach successfully reproduces the induced-gate noise and the cross-correlation noise between drain and gate for short channel MOSFETs without additional model parameters. In particular, the gate noise characteristics at GHz frequencies are accurately captured. The newly developed high-frequency noise model is implemented in the complete surface-potential based MOSFET model HiSIM (Hiroshima-university STARC IGFET Model) for circuit simulation

I. Introduction

The technology development for scaling the gate length down to the sub-100nm regime promises to accomplish RF applications based on MOSFET technology. Therefore, the impotance of analyzing and predicting the noise characteristics in MOSFETs is increasing in particular for RF analog design [11]. Figure 1 shows schematically the current noise characteristic of MOSFETs as a function of frequency . At low frequency the noise dominates, while at higher frequencies (> 10KHz) the thermal noise and the induced-gate noise become obvious, inducing also the cross-correlation noise. It has been demonstrated that the thermal noise characteristic of short-channel MOSFETs is determined by the surface-potential distribution along the channel [9]. In the GHz frequency range the high frequency carrier dynamics has to be considered explicitly. Fig. 1. Typical example of measured drain current noise spectral intensity as function of frequency . Three different noise mechanisms are depicted. The noise is dominant at low frequency. The thermal noise and the induced-gate noise become obvious at higher frequency.