Study on development of cluster ion implantation system for LSI

我们研制了气体团簇离子注入装置，它具有（a）浅溅射，（B）形成非常平坦的表面，（c）低损伤的表面清洗，（d）高速溅射和（e）形成质量较好的薄膜的高潜力。与单体离子辐照相比，团簇离子辐照的损伤层非常小，这是由于团簇中组成原子的能量相对较低。此外，由于高能量密度辐照的影响，用气体团簇离子溅射金属、半导体和绝缘体薄膜的溅射产额比用单体离子溅射的大几十到几百倍。结果表明，气体团簇辐照后表面非常平整，说明表面发生了侧向溅射，通过调节团簇离子的能量和尺寸，可以实现浅注入，同时，计算机模拟表明，高能团簇撞击固体表面时，团簇组成原子之间发生了多次碰撞，观察到了许多异常现象.

We have developed gas cluster ion implantation apparatus, which has a high potential for (a) shallow implantaiton, (b) very flat surface formation, (c) low damage surface cleaning, (d) high rate sputtering and (e) formation of better quality thin film.The effects of energetic Ar and CO_2 cluster on solid surfaces have been studied for different energies and sizes of cluster. The damaged layr by cluster ion irradiation was very small in comparison with the monomer ion irradiation, which is due to comparatively low energy of constituent atom of the cluster. In addition, the sputtering yield from metal, semiconductor and insulator films, using gas cluster ion, was larger by a few tens to hundreds times than that for the case of monomer ion because of the effect of high energy density irradiation. A very flat surface was obtained after irradiation of gas cluster, which indicates lateral sputtering at the surface.It was also possible to achieve the shallow implantation by adjusting the energy and size of cluster ion.Furthermore, computer simulation showed that when energetic cluster hit a solid surface, multiple collisions between cluster constituent atoms occurred and many unusual effects were observed.