Detection of Trace Water in Phosphine with Cavity Ring-down Spectroscopy

Published

January 1, 2003

Author(s)

Susan Y. Lehman, Kristine A. Bertness, Joseph T. Hodges

Abstract

Water is a detrimental impurity even at concentrations of 10 nmol/mol or less in source gases for compound semiconductor epitaxial growth. Oxygen complexes from water incorporation cause degraded luminescent efficiency and reduced minority carrier lifetimes. Most techniques for detecting water in process gases have poor accuracy below 1 υmol/mol and require frequent calibration and control of ambient humidity. Cavity ring-down spectroscopy (CRDS), in contrast, makes use of a fundamental physical property of H₂O molecules-the optical absorption line strength-and a time constant measurement to provide a water concentration value with high precision and low uncertainty even in the nmol/mol range. We describe the CRDS technique and present the first CRDS measurements of trace H₂O contamination in unpurified and purified phosphine. We also report secondary ion mass spectrometry (SIMS) measurements of the O concentration profiles within a multi-layer film grown using molecular beam epitaxy (MBE) in which respective film layers were grown with the purified and unpurified phosphine previously characterized by CRDS.

Proceedings Title

J. of Crystal Growth
(Special issue for the proceedings of the 14th American Conference on Crystal Growth and Epitaxy)

Volume

250

Conference Dates

August 4-9, 2002

Conference Location

Seattle, WA, USA

Pub Type

Conferences

Keywords

AlInP, cavity ring-down spectroscopy, phosphine, water

Citation

Lehman, S. , Bertness, K. and Hodges, J. (2003), Detection of Trace Water in Phosphine with Cavity Ring-down Spectroscopy, J. of Crystal Growth (Special issue for the proceedings of the 14th American Conference on Crystal Growth and Epitaxy), Seattle, WA, USA (Accessed May 19, 2024)