Formation of Al_xGa_1−xSb films over GaSb substrates by Al diffusion

¹ Dep. Física de Materiales, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain
² Instituto Tecnológico e Nuclear, E. N. 10, 2685-953 Sacavém, Portugal
³ Centro de Física Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisboa, Portugal
⁴ Nanoscale Physics Research Laboratory, School of Physics and Astronomy The University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK

Corresponding author: carmen.herrero@uam.es

Received: 4 July 2003
Accepted: 28 January 2004
Published online: 15 July 2004

Abstract

GaSb and AlSb are very interesting semiconductors widely used in multiple applications such as optoelectronics or thermophotovoltaic cells. AlSb has higher band gap than GaSb but very similar lattice parameter, which allows the fabrication of lattice-matched films with different energy band gap over GaSb substrates. Moreover the ternary alloys, in the system Al_xGa_1−xSb, are very interesting for semiconductor device engineering where the capacity of creating lattice-matched heterostructures with different band gap is very important. In this work, we present a study on the formation of Al_xGa_1−xSb films on GaSb substrates by Al diffusion. Al thin films were evaporated over GaSb substrates and then annealed with different time and temperature conditions. RBS measurements has been performed to analyze the diffusion profile and to calculate the thickness of the Al_xGa_1−xSb films. The dependence of the characteristics of the films with annealing time and temperature is analyzed. EDAX and XRD analysis have been performed to calculate the specific composition of the alloy depending on the film growth parameters