Fabrication and applications of rough silicon surfaces.

摘要

The fabrication of rough Si surfaces with control of the roughness density, roughness length scale, and morphology on a nanometer scale is disclosed using 1) a low pressure chemical vapor deposition (CVD) process, typically in the 1 - 5 mTorr range, and 2) initial surface conditions and operating parameters such that initial growth is nucleation-controlled, e.g., using a thermal SiO2 surface which is relatively unreactive to SiH4 at an operating temperature below about 700 DEG C, and typically in the range of 500 - 600 DEG C. This broad temperature window enhances the feasibility of manufacturing rough silicon surfaces with broad applications. Further, various methods are presented for achieving surface pretreatment to control the size and density of the initial nuclei preparatory to the performance of the foregoing fabrication process. In addition, a method is disclosed for producing on a substrate surface, directly and in-situ, a pattern of submicrometer sized dots such that the dot center surface density and the total dot surface area coverage can be precisely controlled, using the features of the fabrication process with additional steps to achieve the desired dots. Particular applications include fabricating rough Si surfaces as (1) electrodes for high capacitance density structures for high density DRAM and (2) as substrates for low-stiction magnetic disks. <IMAGE>