Low energy ion beam deposition with positive and negative ions experimentsto and modeling of subsurface growth

Ion beam deposition with mass-analyzed positive and negative ions is a new technique for depositing thin films under well-characterized conditions. Wi th Positive And Negative ion Deposition Apparatus (PANDA) the simultaneous deposition of positive and negative ions under ultra-high vacuum conditions as well as the use of single beams is possible. In the present contributio n we present a subplantation model for low-energy ion species including spu ttering and decoverage during sputtering. With the related program code it is possible to get composition profiles as well as a comparison between the arrival ion fluence and the subplanted amount. The results of the model ar e compared to carbon and gold depositions on silicon wafers. It is shown, t hat in both cases of carbon and gold subplantation an almost linear deposit ion behaviour is found for fluences less than 10(18) ions/cm(2). For carbon depositions that nearly linear behaviour arises from the similar and moder ately low self-sputtering yields and for gold subplantations it is due to s urface silicon which protects the underlying gold from being sputtered. (C) 1999 Elsevier Science B.V. All rights reserved.