Ge-Related Interfacial Defects in Sige Alloy Structures

Abstract

AbstractThis paper reports etching results supporting the identification of the SG1 center as a germanium dangling bond defect at the interface between an oxide and crystalline SiGe. The presence of this defect is significant because, like an analogous center in Si-based systems, it may alter the operation of any microelectronic or micro-optical device which incorporates an interface between SiGe and an overlying oxide. The samples examined are oxygen implanted SiGe layers in which the SG1 center is believed to occur at the interface between oxide precipitates and SiGe. Because of the center's apparent relation to the oxide precipitates distributed through layers of the sample, a depth profile assists in confirming the interfacial nature of the defect. We obtain a depth profile by comparing electron paramagnetic resonance (EPR) spectra of samples etched to decreasing thickness. EPR spectra indicate that the SG1 center decreases with depth in a manner that when correlated to a cross sectional transmission electron micrograph confirms the association with SiO2 and supports its location at the SiGe/SiO2 precipitate interface.