二次退火对Al/Ti/n-GaN/Si欧姆接触的影响

Effect of secondary annealing on Al/Ti/n-GaN/Si ohmic contacts

采用热壁外延的方法在硅衬底上生长出n-GaN晶体,制成了Ti/Al双层电极的欧姆接触。通过对不同退火条件下的I-V特性曲线、X射线衍射及二次离子质谱分析,揭示了界面固相反应对该接触的影响,并提出了一种新的二次退火的方法。结果表明,经过二次退火后,Al、Ti、GaN发生了界面固相反应,其接触性能明显提高。

A hot-wall epitaxial method was used to grow n-GaN crystals on Si substrates,and ohmic contacts were realized by depositing Ti/Al electrodes on them.By analyzing the I-V curves,the XRD and SIMS spectra at different annealing conditions,effects of interface solid state reactions on contacts were revealed,and a new method named secondary annealing was proposed.The result suggested that after secondary annealing interface solid state reactions were observed among Al ,Ti and GaN,the contact properties were improved greatly.