AVS 51st International Symposium
    Electronic Materials and Processing Monday Sessions
       Session EM-MoP

Paper EM-MoP5
Application of IR Variable Angle Spectroscopic Ellipsometry to the Determination of Free Carrier Concentration in n@super ++@ Germanium

Monday, November 15, 2004, 5:00 pm, Room Exhibit Hall B

Session: Poster Session
Presenter: D.W. Thompson, University of Nebraska-Lincoln
Authors: D.W. Thompson, University of Nebraska-Lincoln
N.J. Ianno, University of Nebraska-Lincoln
K. Zhou, University of Nebraska-Lincoln
Correspondent: Click to Email
Free carrier concentration profiles were determined by Fourier Transform Infrared (FTIR) variable angle spectroscopic ellipsometry in arsenic doped n@super ++@ germanium. This technique exploits carrier absorption in the mid-infrared range and combines the sensitivity of ellipsometry with a simple Drude free carrier absorption model to determine the carrier profile. The germanium was doped from an arseno silica spin-on source in an open tube furnace under a reducing atmosphere. Peak dopant concentrations were in excess of 10@super 19@/cm@super 3@ over depths greater than 10 @microns@ as determined by secondary ion mass spectrometry (SIMS). Shallower profiles were more effectively detected using ellipsometry. The optical modelling scheme approximated the depth profile of the carrier concentration using a large number of discrete layers. The effect of using different functional dependences such as Gaussian and error function was compared.