TEM characterisation of an interfacial layer between silicon and glass

An interfacial layer has been observed between deposited silicon thin films and glass substrates. Experimental evidence indicates that this thin interfacial layer is formed due to the use of the RCA standard cleaning procedure on Corning Code 7059 and 1737 glasses. In this study cross sectional TEM and EDX analysis on Corning Code 7059 glass shows that this layer is silica rich and verifies its formation due to selective leaching of barium, alumina and boron in the glass surface. The layer shows an abrupt boundary with the glass substrate but there is a composition gradient within the glass substrate that extends ∼50 nm beyond the interface revealed in the TEM micrograph. This interfacial layer is of technological interest because it can provide a physical barrier and/or chemical sink for the out diffusion of impurities.