University of Wisconsin-Madison

1. University of Wisconsin-Madison Materials Research Science & Engineering Center on Nanostructured Interfaces UW MRSEC DMR-0520527 Juan J. de Pablo, PI IRG 1: Influence of Surface Chemical Modification on Charge Transport Properties in Ultrathin Silicon Membranes Shelley A. Scott, Weina Peng, Arnold M. Kiefer, Hongquan Jiang, Irena Knezevic, Donald E. Savage, Mark A. Eriksson, and Max G. Lagally Ultrathin silicon membranes are strongly influenced by the physical and chemical condition of the surface. We have recently demonstrated the controlled effect of modifying the surface through the use of HF-etching and an environment with low humidity. The result of such surface preparation and treatment is a conductivity in the ultra-thin silicon membrane that is significantly larger than can be explained through defect-free surfaces and doping, indicating that the surface and interface conditions in fact enhance conduction under these circumstances. These measurements have two implications: first, they point to the need to control the surface if one wishes to fabricate devices in ultra-thin silicon layers. In conventional microelectronics, this control takes the form of highly controlled SiO2. If one wishes to study transport perpendicular to the surface, other methods will be required. Second, the surface-sensitivity itself offers potential for new applications, if the interaction between the surface and the thin film can be well understood, instead of simply minimizing the consequences through high doping, or overwhelming the effect with a high gate field (as is done, e.g., in traditional transistor applications). S. A. Scott, W. Peng, A. M. Kiefer, H. Jiang, I. Knezevic, D. E. Savage, M. A. Eriksson, and M. G. Lagally, “Influence of Surface Chemical Modification on Charge Transport Properties in Ultrathin Silicon Membranes.” ACS Nano3, 1683 (2009).