Mixed orientation Si-Si interfaces by hydrophilic bonding and high temperature oxide dissolution

Abstract

In this paper, we describe a "quasi-hydrophobic" bonding method in which ultrathin (<1-2 nm) oxide, present on wafer surfaces during bonding, is removed after bonding by a high temperature oxide dissolution anneal to leave the desired direct Si-to-Si contact at the bonded interface. We show that the direct-silicon-bonded (DSB) interfaces produced by this method are clean enough to allow implementation of a recently described amorphization/templated recrystallization technique for changing the orientation of selected DSB layer regions from their original orientation to the orientation of the underlying handle wafer. We then present results from a related study on the dissolution of oxide layers disposed between a Si substrate and a polycrystalline overlayer, and discuss mechanisms most likely to be operative for our oxide dissolution observations. © 2007 The Electrochemical Society.