摘要
本文用X射线双晶衍射术,结合摇摆曲线的计算机模拟和电学测量,研究了 180keV Si+注入GaAs(100)样品及其退火过程中的结构变化.结果表明,注入态时Si原子基本上处在基体中的间隙位上,使点阵产生膨胀,在退火过程中逐渐进入替代位,但这一替代过程进行得并不彻底.当剂量高于 1×10^(13)cm^(-2)时,注入态就显著地产生了间隙Si原子进入替代位的过程.当剂量达到 1×10^(15)cm^(-2)时,经 800℃ 0.5 小时的炉退火仍然不能消除离子注入所引起的损伤和应变,大量Si原子留在间隙位上,使激活率难以提高.分析表明,空位和应力在Si原子从间隙位到替代位的过程中起了很大的作用,是GaAs中Si离子注入产生饱和现象的.主要原因.
The 180keV Si^+ implanted and annealed GaAs(100) wafers are investigated by X-ray dou-ble crystal diffraction(DCD),accompanied by measuring the electrical properties and simula-ting the double-crystal rocking curves (RCs).The results show that the implanted Si atoms aregenerally at the interstitial sites to expand the crystal lattice while implanting,and then transfer-red to the substitutional sites after annealing,but this transfer can not completely finish.It is obviously that the Si atoms.have transferred from interstitial sites to substitutional siteswhile implanting at a high dose of more than 1×10^(13)cm^(-2).Though the specimen are annea-led at 800℃ for 30 minutes,the implantation induced crystal lattice damage and strain stillremain at the dose of 1×10^(15)cm^(-2), that is a great number of silicon atoms are still at intersti-tial sites,and the activation efficiency can not be arised.Further analyses show that the holesand the strain in the implanted layer play a main role to transfer interstitial silicon atoms tothe substitutional sites and induce strain saturation effect during implantation.
基金
中国科学院上海冶金所离子束开放实验室青年基金
