Non-Contact Determination of Free Carrier Concentration in n-GaInAsSb

Published

January 1, 2004

Author(s)

James E. Maslar, Wilbur S. Hurst, C Wang, D A. Shiau

Abstract

GaSb-based semiconductors are of interest for mid-infrared optoelectronic and high-speed electronic devices. Accurate determination of electrical properties is essential for optimizing the performance of these devices. However, electrical characterization of these semiconductors is not straightforward since semi-insulating (SI) GaSb substrates for Hall measurements are not available. In this work, the capability of Raman spectroscopy for determination of the majority carrier concentration in n-GaInAsSb epilayers was investigated. Raman spectroscopy offers the advantage of being non-contact and spatially resolved. Furthermore, the type of substrate used for the epilayer does not affect the measurement. However, for antimonide-based materials, traditionally employed Raman laser sources and detectors are not optimized for the analysis wavelength range dictated by the narrow band gap of these materials. Therefore, a near-infrared Raman spectroscopic system, optimized for antimonide-based materials, was developed.Ga0.85In0.15As0.13Sb0.87 epilayers were grown by organometallic vapor phase epitaxy with doping levels in the range 2 to 80 x 1017 cm-3, as measured by secondary ion mass spectrometry. For a particular nominal doping level, epilayers were grown both lattice matched to n-GaSb substrates and lattice-mismatched to SI GaAs substrates under nominally identical conditions. Single magnetic field Hall measurements were performed on the epilayers grown on SI GaAs substrates, while Raman spectroscopy was used to measure the carrier concentration of epilayers grown on GaSb and the corresponding SI GaAs substrates. Compared to Hall measurements, Raman spectra indicated that the GaInAsSb epilayers grown on GaSb substrates have higher free carrier concentrations than the corresponding epilayers grown on SI GaAs substrates under nominally identical conditions. This is contrary to the assumption that for nominally identical growth conditions, the resulting carrier concentration is independent of substrate, and possible mechanisms will be discussed.

Proceedings Title

Progress in Compound Semiconductor Materials--Electronic and Optoelectronic Applications, Symposium on | 3rd | Progress in Compound Semiconductor Materials III-Electronic and Optoelectronic Applications | Materials Research Society

Volume

799

Conference Dates

December 1-4, 2003

Conference Title

Materials Research Society Symposium Proceedings

Pub Type

Conferences

Keywords

GaInAsSb, Gallium indium arsenide antimonide, non-contact carrier density measurement, Raman spectroscopy

Citation

Maslar, J. , Hurst, W. , Wang, C. and Shiau, D. (2004), Non-Contact Determination of Free Carrier Concentration in n-GaInAsSb, Progress in Compound Semiconductor Materials--Electronic and Optoelectronic Applications, Symposium on | 3rd | Progress in Compound Semiconductor Materials III-Electronic and Optoelectronic Applications | Materials Research Society (Accessed April 26, 2024)