Dynamics of light-induced separation of gases

Abstract

In reactive ion etching (RIE) processes of vertical metal oxide semiconductor (MOS) devices, damages caused by ion bombardment at oblique incidence may affect the device performance. In this study, damage formation on Si surfaces by energetic hydrogen and halogen ions has been examined for different angles of incidence with the use of a multi-beam system. The beam experiments and molecular dynamics simulations have shown that the depth of a Si damage layer caused by H þ ion injections has weak dependence on the angle of incidence. It is also found experimentally that the Cl þ or Br þ ion etching yield of a Si substrate that is damaged by energetic hydrogen ions prior to Cl þ or Br þ ion injections is essentially the same as that of the undamaged Si substrate. The results indicate that, in the etching process of vertical MOS gate structures, surface bombardment by energetic hydrogen ions even at oblique incidence may cause several-nanometer deep damages to the Si channels but etching yields for the gate fabrication are unlikely to be altered by the surface damages. #