II. Physikalisches Institut, Universität zu Köln, Zülpicher Strasse 77, D-50937 Cologne, Germany.
Nanotechnology. 2010 Feb 26;21(8):85301. doi: 10.1088/0957-4484/21/8/085301. Epub 2010 Jan 25.
We present ion beam erosion experiments performed in ultrahigh vacuum using a differentially pumped ion source and taking care that the ion beam hits the Si(001) sample only. Under these conditions no ion beam patterns form on Si for angles theta < or = 45 degrees with respect to the global surface normal using 2 keV Kr+ and fluences of approximately 2 x 10(22) ions m(-2). In fact, the ion beam induces a smoothening of preformed patterns. Simultaneous sputter deposition of stainless steel in this angular range creates a variety of patterns, similar to those previously ascribed to clean ion-beam-induced destabilization of the surface profile. Only for grazing incidence with 60 degrees < or = theta < or = 83 degrees do pronounced ion beam patterns form. It appears that the angular-dependent stability of Si(001) against pattern formation under clean ion beam erosion conditions is related to the angular dependence of the sputtering yield, and not primarily to a curvature-dependent yield as invoked frequently in continuum theory models.
我们呈现了在超高真空条件下使用差分抽气离子源进行的离子束侵蚀实验，确保离子束仅撞击 Si(001) 样品。在这些条件下，使用 2 keV Kr+ 和大约 2 x 10(22)离子 m(-2) 的通量，对于相对于全局表面法线的角度 theta < or = 45 度，在 Si 上不会形成离子束图案。实际上，离子束会导致预先形成的图案变得平滑。在这个角度范围内，同时溅射沉积不锈钢会产生各种图案，类似于先前归因于清洁离子束诱导的表面轮廓失稳的图案。只有在掠入射时，60 度 < or = theta < or = 83 度，才会形成明显的离子束图案。看来，在清洁离子束侵蚀条件下 Si(001) 对图案形成的角度依赖性稳定性与溅射产额的角度依赖性有关，而不是像连续体理论模型中经常提到的曲率依赖性产额那样主要与曲率依赖性产额有关。
