不同退火温度对4H-SiC金半接触的影响

Effect of Different Annealing Temperature on 4H-SiC Schottky Diodes

采用高真空电子束蒸发法制作了基于4H-SiC外延材料的肖特基二极管,其中欧姆接触材料为Ti/Ni,肖特基接触材料为Ni。常温下,电流-电压(I-V)测试表明Ni/4H-SiC肖特基二极管具有良好的整流特性,热电子发射是其主要输运机理。对比分析不同快速退火温度下器件的I-V特性,实验结果表明875℃退火温度下欧姆接触特性最好,400℃退火温度下器件肖特基接触I-V特性最好,理想因子为1.447,肖特基势垒高度为1.029eV。

Electron beam evaporation was used to deposit metal Ni forming the Schottky contact and Ti/Ni ohm- ic contact respectively in high vacuum ambient. Ni/4H-SiC Schottky barrier diodes were made in domestic n-type 4H-SiC epitaxial material. Measurements of the I-V characteristics of these diodes showed the devices had good ohmic contact and rectifying property, and thermionic emission current was the dominant conduction mechanism for these Schottky contacts. The I-V characteristics of device were analyzed under different annealing temperature. The experimental results showed that ohmic contact annealed at 875 ℃ was the best and I-V characteristics of these Schottky diodes annealed at 400℃ was the best, whose ideality factor was 1. 447 and the Schottky barrier height was 1. 029 eV.