摘要
用传输线模型对 n型 Al Ga N(n- Al Ga N)上 Au/ Pt/ Al/ Ti多金属层欧姆接触进行了接触电阻率的测量 .在85 0℃退火 5 min后 ,测得欧姆接触电阻率达 1.6× 10 - 4Ω· cm2 .经 X射线衍射分析 ,Au/ Pt/ Al/ Ti/ n- Al Ga N界面固相反应得出在 5 0 0℃以上退火过程中 ,Al Ga N层中 N原子向外扩散 ,在 Al Ga N表面附近形成 n型重掺杂层 ,导致欧姆接触电阻率下降 ;随退火温度的升高 ,N原子外扩散加剧 ,到 80 0℃以上退火在 Au/ Pt/ Al/ Ti/ n- Al Ga N界面形成 Ti2 N相 。
By the means of the transmission line model,the resistivity ( R C) of the Ohmic contact between Au/Pt/Al/Ti multilayer and n type AlGaN (n AlGaN) is tested.After annealing at 850℃ for 5mim,the R C is reached as low as 1 6×10 -4 Ω·cm 2.Based on the analysis of XRD measurements,it is concluded that N atoms in n AlGaN layer diffuse out and much more N vacancies are formed after the annealing temperatures reached 500℃ and above.It induces the heavy n type doped layer near the n AlGaN surface,and thus,it leads to the decrease of R C.With increasing of the annealing temperature,more N atoms in n AlGaN layer diffuse out and react with Ti atoms.Ti 2N at the interface between Au/Pt/Al/Ti and n AlGaN is formed after annealing at 800℃,resulting in the R C further decreases.
基金
国家重点基础研究专项 (G2 0 0 0 0 683 )
国家自然科学基金(6980 60 0 6
699760 14及 699870 0 1)
国家高科技发展计划资助课题~~
