自己バイアスチャネルダイオードの電流電圧特性解析シミュレーション

抄録

A self-biased channel diode (SBCD) that self-biases a channel diode using a DMOSFET structure has recently been proposed. In the present paper, an analytical simulation method, based on a drift-diffusion model that takes into account the physics of the SBCD, is described and the simulation results are presented. The simulation results are seen to be in good agreement with the experimental results. An increase ratio of a reverse leakage current of the SBCD for temperature is significantly less than that of the Schottky barrier diode (SBD). This relative insensitivity of the SBCD reverse current to rising temperature can be explained in terms of the temperature dependence of the parameters composed of the reverse leakage current by the analytical simulation. Furthermore, the power loss is simulated for a SBCD with a thin gate oxide layer, integrated into a high-density DMOSFET cell. The SBCD impurity profile is chosen to correspond to an approximate minimum power loss at 75°C for a gate oxide thickness of 3nm. Under these conditions, the SBCD exhibits a power loss intermediate between that of the Ti-SBD and Cr-SBD in the temperature range 25-75°C. However, at high temperatures, the power loss in the SBCD is lower than that for the Ti-SBD or Cr-SBD, which easily undergo thermal runaway.