退火温度对Au/Ti/4H-SiC肖特基接触特性的影响

Effects of Annealing Temperature on the Characteristics of Au/Ti/4H-SiC Schottky Contact

采用电子束蒸发法在4H-SiC表面制备了Ti/Au肖特基电极,研究了退火温度对Au/Ti/4H-SiC肖特基接触电学特性的影响。对比分析了不同退火温度下样品的电流密度-电压(J-V)和电容-电压(C-V)特性曲线,实验结果表明退火温度为500℃时Au/Ti/4H-SiC肖特基势垒高度最大,在J-V测试和C-V测试中分别达到0.933 e V和1.447 e V,且获得理想因子最小值为1.053,反向泄漏电流密度也实现了最小值1.97×10^(-8)A/cm^2,击穿电压达到最大值660 V。对退火温度为500℃的Au/Ti/4H-SiC样品进行J-V变温测试。测试结果表明,随着测试温度的升高,肖特基势垒高度不断升高而理想因子不断减小,说明肖特基接触界面仍然存在缺陷或者横向不均匀性,高温下的测试进一步证明肖特基接触界面还有很大的改善空间。

The Ti/Au Schottky electrode was prepared on 4H-SiC surface by electron beam evaporation method. The effects of annealing temperature on the electrical characteristics of Au/Ti/4H-SiC contact were investigated. The current density-voltage（ J-V） and capacitance-voltage（ C-V） characteristics curves of the sample at different annealing temperatures were compared and analyzed. The experimental results indicate that at the annealing temperature of 500 ℃,a maximum Schottky barrier height of Au/Ti/4H-SiC is achieved and the corresponding values are 0. 933 e V（ J-V） and 1. 447 e V（ C-V）. The ideal factor is the lowest value of 1. 053,the reverse leakage current density also reaches the lowest value of 1. 97×10^-8A/cm^2 and the highest breakdown voltage is 660 V. The J-V variable temperature test of the Au/Ti/4H-SiC samples with an annealing temperature of 500 ℃ was carried out. The test results show that with the increase of the measurement temperature,the Schottky barrier height increases continuously,while the ideal factor decreases continuously. It is indicated that some defects or lateral inhomogeneity still exist in the Schottky contact interface. High temperature measurement further demonstrates that the Schottky interface maybe greatly improved.