The Influence of Incidence Angle on Damage Production in In⁺ Ion Implanted Si

Abstract

One set of models (1) of ion irradiation enhanced reactive gas etching of materials, including Si, suggests that increased reaction rates occur as a result of surface damage production by the irradiation. If this is the case then etching rates should depend upon the incident angle of irradiation since this should modify the surface damage density as a result of varying energy deposition density near the surface. Although theoretical predictions of surface damage can be made in the limit of low ion fluence (2) these do not apply for high incidence angles (relative to the surface normal) since collision cascades are incompletely developed near a free surface, nor at high fluence where individual disordering events accumulate and overlap (3). Numerical simulations are possible, and some such data will be presented in this paper but, of course, experimental observation is the only really valid method. Whereas some results of the dependence on incident angle upon ion ranges and range distributions have been published (4) no such data exists for the damage production. This paper reports the first such results.