AVS 45th International Symposium
    Applied Surface Science Division Friday Sessions
       Session AS+VT-FrM

Paper AS+VT-FrM10
Laser Assisted Etching of InP Studied with XPS

Friday, November 6, 1998, 11:20 am, Room 307

Session: Application of Surface Analysis Techniques to Semiconductor Technology
Presenter: D.M. Wieliczka, University of Missouri, Kansas City
Authors: D.M. Wieliczka, University of Missouri, Kansas City
J.M. Wrobel, University of Missouri, Kansas City
C.E. Moffitt, University of Missouri, Kansas City
J.J. Dubowski, National Research Council of Canada
Correspondent: Click to Email
X-ray Photoelectron Spectroscopy (XPS) and Scanning Electron Microscopy (SEM) have been used to study the surface chemistry and morphology of InP wafers after photo-chemical etching of the surface. The etching process employed 308 nm illumination from a XeCl excimer laser in conjunction with a low pressure atmosphere of 10%/90% Cl@sub 2@/ He mixture. The samples were exposed to laser radiation with fluences ranging from 73 mJ/cm@super 2@ to 210 mJ/cm@super 2@. The lower fluence is well below the ablation threshold for InP under vacuum conditions. The use of a Kratos AXIS-HS photoelectron spectrometer allowed for mapping the surface chemical composition within the illuminated region and in the vicinity with a 60 µm spot size. Photoelecron spectral lines from In, P, Cl, C, and O were monitored for determining the surface chemical composition and for creating surface maps of the illuminated regions. The results showed a distinct correlation between surface chemical composition and laser fluence. At high fluence levels, the surface composition changed dramatically between the illuminated region and the exterior. Evidence for In-Cl compounds was found within the crater with thermal processes occurring in the region near the crater. At low laser fluence, the etching process showed no thermal effects in the near crater region and produced a crater with minimal Cl incorporation. In addition to the chemical changes with fluence, the surface morphology is dramatically altered. At high fluence levels, SEM images indicate the etched surface was rough and deposits of ablated material were left in the vicinity of the crater. At low fluence the images indicate a better surface morphology. This work was supported by the University of Missouri Research Board.