Author:
Koga Yoshihiro,Yamada Shunsuke,Tanaka Shuji,Kurita Kazunari
Abstract
Abstract
We propose the use of a laminated wafer with a conductive diamond layer for forming cavities as an alternative silicon-on-insulator wafer for micro-electro mechanical system (MEMS) sensors. Since this wafer has no insulator such as a buried oxide (BOX) layer but a conductive layer, it is not charged during plasma treatment in MEMS sensor fabrication processes. The conductive diamond layer was formed on a base wafer doped with boron of more than 2 × 1021 atoms cm−3 by microwave-plasma-enhanced chemical vapor deposition. The resistivity of this layer was 0.025 Ω cm, and this layer can be selectively etched to a base wafer made of silicon crystal, such as a BOX layer. In addition, a silicon wafer can be bonded to its layer without voids with gaps of more than 2 nm by surface-activated bonding. Therefore, we believe that the laminated wafer studied here is useful for the fabrication processes for MEMS sensors that may otherwise be damaged by plasma treatment.
Subject
General Physics and Astronomy,Physics and Astronomy (miscellaneous),General Engineering