Standardizing large format 5" GaSb and InSb substrate production

Abstract

In this paper we report on the maturation of large diameter GaSb and InSb substrate production and the key aspects of product quality and process control that have enabled a level of standardization to be achieved that is on par with mass produced compound semiconductor materials such as GaAs and InP. The evolution of commercial production processes for the crystal growth, wafering and epitaxy-ready polishing of antimonide substrates will be discussed together with specific reference to the process tool sets and production methodologies that have transformed a niche material in to one that has set new standards for wafer level product quality, conformity and control. Results will be presented on the production of single crystal >/=6” ingots grown by a modified version of the Czochralski (LEC) technique. Crystal defect mapping will demonstrate that industry standard InSb (211) growth processes have been refined to consistently deliver ultralow dislocation density substrates. Statistical process control data will be presented for large format 5” epitaxy ready finishing processes and compared alongside in-house data for GaAs and InP. Various surface analytical tools are used to characterize 5” InSb and GaSb substrates and our method of providing a unique characterization ‘finger print’ with each substrate discussed. We conclude that improvements in InSb and GaSb product quality and consistency have been driven by the industry’s persistent need to improve device performance and yield. Whilst substrate size requirements in antimonide wafer production may have peaked, we will discuss how to moving to the next step in substrate diameters, 6”, is very attainable and within relatively short timescales too.