Advanced Composite Substrate Development of CD-Based-II-VI Materials for IR Applications

摘要

Through its mature materials development and ability to detect any wavelength of interest within the infrared (IR) spectrum HgCdTe is currently and is positioned to remain, the leading choice among IR sensing material for high performance applications. However, a major roadblock lies ahead for HgCdTe IR systems. With array sizes increasing through the need for higher resolution systems, current substrate technology based on bulk CdZnTe material will not be suitable for future systems. The lack of CdZnTe bulk wafer size available (currently limited to less than 7 x 7 sq cm) and high cost in the market place ((caret)$250/sq cm) will stop the progression of HgCdTe based IR systems. To mitigate these and other issues, the Army Research Laboratory (ARL) has played a key role in the development of Si-based composite substrate technology for HgCdTe material applications. By transitioning current molecular beam epitaxial (MBE) HgCdTe materials technology to a novel Si-based composite substrate, physical size limitations of HgCdTe material is no longer an issue. Furthermore, besides material cost, manufacturing cost will also be reduced as more dies per water will be processed. Specifically, CdTe material technology grown on Si substrates has already been successfully developed for short-wave and mid-wave detector arrays. However, it is recognized that ternary and quaternary Cd-based II-VI materials with lattice matching to that of HgCdTe may be even better suited for HgCdTe growth and IR device processing. particularly for long- wavelength HgCdTe detector arrays. ARL has taken the lead in this research area for the Army.