IEEE Workshop on Wide Bandgap Power Devices and Applications in Asia (WiPDA Asia 2018)

318 / 2017-12-08 16:17:40

A Lateral SiC SBD Temperature Sensor with Barrier Height Inhomogeneities

SiC,SBD,temperature,sensor,SBH,inhomogeneity

Plenary track > Device characterization and modeling

In this work, a lateral SiC Schottky Barrier Diode(SBD) temperature sensor is built by Silvaco TCAD. This SiC SBD temperature sensor is integrated in the pwell of VDMOSFETs, so that the temperature sensor could monitor temperature of PN junction and the channel of VDMOSFETs. As is well-known, there are so many defects on the implanted surface, those defects induce SBI(Schottky Barrier Inhomogeneities). In order to evaluate influence of SBI, some parallel SBDs with different SBH(Schottky Barrier Height) and area is set by Silvaco TCAD and the area of specific SBH is depend on Guassian distribution while effective area is occupy 3% of total Schottky area, and nonuniform current distribution at Schottky electrode is found. Sensitivity is from 0.851mV/K to 1.124mV/K is extracted from I-V-T curve of lateral SiC SBD temperature sensor when operating current is from 2uA to 0.1mA with operating temperature range is from 300K to 575K. And then, in order to predict operating current of this kind of temperature sensor or further predict the I-V characteristics of SBD with SBI, a compact model for SiC SBD with inhomogeneous SBH is presented. This mathematic model mainly based on two kinds of measurement, average SBH is extracted from C-V curve in different temperature, effective SBH and the ideality factor are extracted from I-V curve in different temperature. Further, the variance of SBH distribution is calculated out by effective SBH and average SBH. In addition, we found the linear relationship between effective SBH and ideality factor, so, effective SBH could be expressed by ideality factor in fitting. Further, we consider the variation of current density on lateral electrode. Finally we brought all of those data into Gaussian distribution, and will obtain the I-V characteristics of SBD consider with BHI in different temperature.