Growth of Alloy Semiconductors with Travelling Magnetic Fields

The goal of this program is to build a system for growth of alloy semiconductors with electro-magnetic stirring, and to use this system to grow AlGASb crystals.  The growth system will be built to be easily configurable for crystal growth by the Vertical Bridgman,and Traveling Heater methods. It will include two different setups for generation of stirring forces in the liquid semiconductor, each with certain advantages.  The design of this growth system and development of the crystal growth processes will be based on the detailed numerical simulation of the electro-magnetically stirred growth of AlGaSb conducted in Phase I.    As part of the Phase II work, we will produce a robust and validated tool for design and analysis of electro-magnetic stirring during crystal growth that will overcome the limitations in commercial simulation codes.  In the second year of this program, the developed hardware and simulation tools will be used to develop crystal growth processes with the goal of producing compositionally-uniform single crystals of AlGaSb.   BENEFIT: Single crystals of alloyed compound semiconductors are critical enabling elements for long wavelength IR (LWIR) detectors and high speed electronics.  In this regard, GaAlSb alloys are of particular interest.  The GaAlSb alloys are semiconductors in which the band-gap can be changed with composition in a wide range:  from 1.6 eV (AlSb) to 0.726 eV (GaSb). Large band gap of the semi-insulating substrates and bulk crystals are needed specially for ultra high-speed terahertz electronic devices and long wavelength sensors.