强流脉冲电子束作用下单晶硅表层缺陷与结构变化

Defects and Microstructures in the Surface Layer of Single-crystal Silicon Induced by High-current Pulsed Electron Beam

为了研究超快变形诱发的非金属材料的微观结构状态,利用强流脉冲电子束(HCPEB)技术对单晶硅进行了辐照处理,并用透射电镜对电子束诱发的表层微观结构进行了分析.实验结果表明,HCPEB辐照后单晶Si表层形成了丰富的缺陷结构,互相平行的螺位错和外禀层错是辐照后最为典型的缺陷结构;同时HCPEB辐照还诱发了密度很高的包括位错圈和SFT在内空位簇缺陷,幅值极大和应变速率极高的表面应力导致的{111}面整体位移可能是大量空位簇缺陷形成的根本原因.此外,HCPEB处理可在单晶Si表面形成纳米和非晶混合结构.

In order to investigate the microstructures of nonmetallic material induced by high-speed deformation, the high-current pulsed electron beam （HCPEB） technique was used to irradiate the single-crystal silicon. The surface microstructures induced by electron beam were studied by transmission electron microscope （TEM）. The experimental results showed that a large number of defect structures were formed by the HCPEB irradiation. Among them, the typical defect structures were the parallel screw dislocations and the extrinsic stacking faults. In the meantime, the HCPEB irradiation induced high density of vacancy cluster defects. The surface stress with very high value and strain rate led to the integral shift of （111） crystal plane, which might be the dominating reason of the formation of the massive vacancy cluster defects. In addition, the mixtures of nanocrystal and amorphous in the surface of single-crystal silicon can be formed by HCPEB technique.