Transmission electron microscopy study of damage layer formed through ion beam induced deposition of platinum on silicon substrate

Ion beam induced deposition is used for nanofabrication operations (e.g., transmission electron microscopy sample preparation) but is still not perfectly understood. Here, the authors describe the use of a wide variety of analytical instruments to develop such an understanding. Pt-films were deposited on native oxide films on silicon (Si) by decomposing trimethyl platinum C5H4CH3Pt(CH3)(3) with focused electron or gallium ion beams. Unlike electron beam induced deposition, ion beam induced deposition produces a deep and complex damage layer below the deposition. It is revealed that the damaged area can be divided into three layers: (1) a white-band with a lower Pt-concentration and concurrent higher carbon (C)-concentration; (2) a-Pt-Si region where amorphized silicon crystal is mixed with Pt, and Pt-particle formation starts somewhere in the middle area; and (3)a-Si, which is silicon amorphized by Ga ions. The change in the diffusion rate of platinum into the amorphized silicon layer plays a crucial role in the formation of the distinct layers. The diffusions are affected by interatomic chemical affinity as well as by concentration, so that the Pt-Si combination initially dominates Pt agglomeration and the combination of C-Si, resulting in the creation of the novel white-band. (C) 2010 American Vacuum Society. [DOI: 10.1116/1.3516651]