SPUTTERING OF COMPOUND SEMICONDUCTOR SURFACES .1. ION-SOLID INTERACTIONS AND SPUTTERING YIELDS

Several phenomena occur on the surface of a solid when being bombarded by energetic ions. A short general review is given of the major ion-solid interactions on compound semiconductor surfaces. An in-depth discussion is presented of the total sputtering yields of component semiconductors. For this discussion, GaAs is assumed to be the prototype compound semiconductor because most experimental measurements exist for GaAs. To exclude any chemical effects in the sputter yields, only the total sputtering yield data for argon ion bombardment of GaAs are compared with the predictions of the major sputtering theories, with particular attention to the Sigmund theory for linear cascade sputtering. Different proposals of each of the parameters in this theory are presented and compared with the GaAs data. These parameters are the surface binding energy, the nuclear stopping power, and the factor a, which represents the fraction of energy available for sputtering. Use of the different parameters results in a large variation in the predictions. Topics also considered are the angle dependence of the sputtering yields, sputter threshold energy, and channeling effects in the sputter yields of compound semiconductors. Spike sputtering effects are evident in the sputtering yields of GaAs by krypton and xenon ions.