Si基MOCVD生长AlN深陷阱中心研究

Investigation of Deep Trap Center of AlN Grown on SiSubstrate

通过 PL 谱和 Raman谱对 MOCVD生长 Si基 Al N的深陷阱中心进行了研究 ,发现三个深能级 Et1 ,Et2 ,Et3,分别在 Ev 上 2 .6 1,3.10 ,2 .11e V.Et1 是由氧杂质和氮空位 (或 Al间隙原子 )能级峰位靠近重合共同引起的 ,Et2 、Et3都是由于衬底 Si原子扩散到 Al N引起的 .在 Si浓度较低时 ,Si主要以取代 Al原子的方式存在 ,产生深陷阱中心Et2 .Si浓度高于某个临界浓度时 ,部分 Si原子以取代 N原子位置的方式存在 ,形成深陷阱中心 Et3.实验还表明 ,即使经高温长时间退火 ,Al N中 Et1 和 Et2

The deep trap center of AlN grown on Si substrate is investigated with PL spectr a and Raman spectra.Three deep trap centers E t1, E t2 and E t3 are found at 2.61,3.10,and 2.11eV above E v,respectively. E t1 is induced by superposition of the peak of O impurities and peak o f N vacancies (or interstitial Al atoms).Because of the high growth temperature, Si atoms diffuse into the AlN layer and take the places of Al atoms and Si-N bo nds are formed.After annealing,when the density of Si is higher than a critical one,some Si atoms take the places of N atoms and Al-Si bonds are formed. E t2 is induced by Si-N bonds and E t3 by Al-Si bonds.It is also fo und that E t1 and E t2,the deep trap centers,are stable even a fter high temperature annealing for several hours.