Chapter 7 - MCT properties, growth methods and characterization

Abstract

This chapter describes Mercury Cadmium Telluride (MCT) characteristics, MCT material growth techniques and MCT material characterization methods. The chapter focuses on recent developments and emerging technologies for MCT. MCT is a very important semiconducting material. MCT is used to fabricate infrared (IR) detectors for military and scientific applications. Three basic MCT material requirements are: large wafer size, small variations in composition and doping across a large wafer, and very few defects across a large wafer. Other material requirements are determined from the specific IR device that is to be fabricated with the MCT material. MCT is a ternary alloy consisting of a solid solution of the two compounds, HgTe and CdTe. For high performance device fabrication, nearly perfect, large area crystalline MCT material is required. There are several methods for MCT crystal growth classified as bulk growth. These crystal growth methods include: quench and anneal or solid state recrystallization (SSR), traveling heater method (THM) or traveling solvent method, Bridgman, slush method, zone melting and Czochralski. There are two main goals for characterization of MCT material. One is to provide accurate data for the parameters of MCT in order to gain scientific understanding of the material and of changes in material properties due to variations in external parameters. The other goal is to have a material characterization method that is suitable for a production environment.