Channel Strain Dependence of Tinv in Strained Si and Sil-xGexFETs: Internal Strain-induced Modification of Chemical Oxidation

Abstract

Self-limiting chemical oxidation behaviors on SiGe channels with biaxial and uniaxial strain are studied to understand the role of the internal channel strain in the interfacial layer (IL) formation. Biaxial strain accelerates chemical oxidation on Si and SiGe regardless of Ge content in the channel, forming a thicker IL in planar FETs. On the other hand, chemical oxidation is not sensitive to uniaxial strain thanks to the less strain in the out-of-plane direction, forming a thinner IL in FinFETs. The universal relationship of Tinv and channel strain from both planar FETs and FinFETs is discussed.