A New Ellipsometry Technique for Interface Analysis: Application to Si-SiO2

Abstract

DuOIc ,epori '; okr~en IQ,' tn. collection of ,nlornsation IS estimated to average i hsour we response. including the time for reviewin instructions. searching existing data W.urceS. 4A~heri.g inC n'iaIn.isg the data needeOd,Z.nd copleting ,I rev-e-ing the ollectiOn Of information. Send comments regarding this burden estimate or any other asoe:: at this collectIonc "orinatieft.-rcluoig sggeston fo reduc ,In hs burden. This document has been approved. for public release and sale, distribution of this document is unlimited. ABSTRACT (Maxcimum 200 words)in this paper we report a new spectroscopic elliPscrettxY technique that overccrnes michof he i~bguiy asocitedwit uesuring an interface under a f ilm. For this technique we match the refractive indiex of the overlayer with an irersion. liquid and then perform spectroscopic ellipsaitry at several angles of incidence. Essentially, the Overlayer is optically (not physically) removed, thereby rendering the ellipsarmetric measurement sensitive to the interfacial layer which is often liai to be optically and chenically different than either substrate or film. The si-SiO 2 interface resulting fran thermal oxidation Of Si, and the evolution Of the interface with annealing is studied using the new techni1que. ABSTRACTIn this paper we report a new spectroscopic ellipsometry technique that overcomes much of the ambiguity associated with measuring an interface under a film. For this technique we match the refractive index of the overlayer with an immersion liquid and then perform spectroscopic ellipsometry at several angles of incidence. Essentially, the overlayer is optically (not physically) removed, thereby rendering the ellipsometric measurement sensitive to the interfacial layer which is often known to be optically and chemically different than either substrate or film. The Si-SiO 2 interface resulting from thermal oxidation of Si, and the evolution of the interface with annealing is studied using the new technique.