SOI wafer fabricated with extremely thick deposited BOX layer using a surface activated bonding technique at room temperature

Abstract

The fabrication cost of bonded silicon on insulator (SOI) wafers for customized power devices is high owing to the high temperature required and the very long fabrication process involving both thermal oxidation and bonding. In addition, SOI wafers are contaminated with metallic impurities during the formation of the buried oxide (BOX) layer and the bonding of a silicon layer on the BOX layer. Therefore, we propose an alternative SOI wafer fabrication method combining BOX layer deposition and surface activated bonding at room temperature in a vacuum without any voids. There is also no fixed charge in the deposited BOX layer, and the breakdown voltage of this layer is 11–12 MV cm−1, the same as that for a thermal oxide layer.

Fabrication of silicon on insulator wafer with silicon carbide insulator layer by surface-activated bonding at room temperature

“…44) In addition, according to previous studies, SAB can fix not only crystalline materials but also noncrystalline materials. 21,31,45) Our results are thus reasonable. 24,29,30) Therefore, we concluded that a silicon wafer (layer) could be fixed to a SiC layer with a capping SiN layer of a base wafer without voids or punch-out dislocations larger than 1 nm by depositing the amorphous adhesive layer containing silicon before bonding.…”

“…A reference sample was fabricated by the PE-CVD of SiO 2 as the insulator layer at 500 °C and fixed by SAB at room temperature. 31)…”

Room-temperature bonded silicon on insulator wafers with a dense buried oxide layer formed by annealing a deposited silicon oxidation layer and surface-activated bonding

“…We firstly studied the SOI wafer with the BOX layer formed by CVD at 500 °C, in order that this layer was dense. 37) This wafer had good characteristics that were a bonding interface and a breakdown electrical field. However, because a CVD process is normally at below 400 °C, the CVD device used at 500 °C has special specs and must be made to order.…”