组合材料方法研究膜厚对Ni/SiC电极接触性质的影响

Effect of Ni thickness on the contact properties of Ni/6H-SiC analyzed by combinatorial method

采用组合材料方法研究了金属Ni膜厚对Ni/SiC接触性质的影响.16个膜厚均为18nm的Ni/SiC电极具有较为一致的肖特基接触性质;膜厚从10nm增加到160nm,肖特基接触的电流-电压(I-V)曲线随膜厚发生显著变化.分析表明这种变化源于膜厚对理想因子n和有效势垒高度ФB的影响.1000℃快速退火后,这些肖特基接触都转变为欧姆接触,Ni2Si是主要的生成物.I-V曲线测试表明,Ni膜厚为30至70nm范围时能稳定得到性质较好的欧姆接触.证实了之前认为Ni/SiC高温退火后富碳层存在一个合适范围以形成良好欧姆接触的结论.

In this paper,combinatorial method was introduced for the first time to disclose the effect of Ni thickness on the Ni/SiC contact properties. Sixteen contacts with the same Ni thickness showed similar Schottky contact properties. The current voltage curves （I-V） were different for the Schottky contacts with different Ni thickness from 10 nm to 160 nm. The effect of the Ni thickness to the ideality factor n and the effective barrier height ФB was found to be the origin of the different Schottky contact properties. After rapid annealed at 1000℃ ,all the contacts showed good linear I-V curves,which indicated the formation of ohmic contacts. Ni2Si was the main reaction product. Comparing the slopes of the IV curves,the contacts with 30—70 nm Ni showed good ohmic contact properties. The results confirmed our previous conclusion about the key role of appropriate carbon-enriched layer （CEL） for the formation of ohmic contacts on SiC.