Fabrication of an ultrathin silicon wafer with a honeycomb structure by the thermal-stress-induced pattern transfer (TIPT) method

Abstract

A 3 µm thick silicon thin film with a textured surface was fabricated successfully by three major steps. First, the silicon thin film was deposited on a sapphire substrate by a plasma-enhanced chemical vapor deposition system. Second, metal paste was printed on the silicon thin film. Third, a thermal treatment was applied on the sapphire substrate. After cooling, the silicon layer, combined with the metal paste, was peeled from the sapphire substrate because of the large differences in the thermal expansion coefficient between the silicon-metal composite layer and the sapphire substrate. An ultrathin silicon wafer of 3 µm thickness was obtained in this study. Furthermore, a silicon layer with a micro-scale and a nano-scale honeycomb structures can be obtained easily by transferring patterns from the well-designed patterned sapphire substrate.