Development of Process to Produce Wafer Scale Zinc Selenide (ZnSe) Crystals

Technical Abstract

This technology program focuses on producing wafer level single crystals of Zinc Selenide (ZnSe). ZnSe is a good alternative to currently used materials (such as periodically poled lithium niobate (PPLN) or quasi phase-matched GaAs structures), for infrared countermeasure applications. ZnSe has a wider band gap, modest nonlinear coefficient, and high transparency from visible to long IR wavelengths. Unfortunately, there exists a lack of high-quality large single crystal ZnSe substrates. We propose a commercial, scalable single crystal growth process for large diameter ZnSe substrates using Physical Vapor Transport (PVT). The Brimrose team has extensive hands-on experience in the growth of ZnSe and similar semiconductors by PVT. PVT inherently has a slow growth rate. However, we have put a great deal of effort into understanding the parameters to enhance the transport rate and have demonstrated the feasibility to do so. Using our novel, proprietary, modified materials processing technique, we routinely produce high quality, single crystals of ZnSe up to 15mm in diameter.  We will further scale up the size during Phase I and Phase II. We will use unseeded growth of ZnSe crystal to prepare oriented seeds for seeded growth to obtain oriented single crystals.

Anticipated Benefits/Potential Commercial Applications

Single crystal ZnSe is an efficient scintillator material for x-ray radiation detectors and imaging devices. These detectors have applications in high energy and nuclear physics, as well as in security screening, medical x-ray imaging, dental imaging, and industrial x-ray imaging. ZnSe can be used to produce blue and white LEDs, and blue lasers. ZnSe is a good substrate material to produce high throughput quasi-phase matched structures for generating high energy infrared lasers.   Transition metal doped ZnSe is a good laser material to produce mid-infrared lasers at room temperature. In addition, this research will advance the Global Strike Operational Imperative’s need to address infrared missile threats.

Key words:

Zinc Selenide (ZnSe), Vapor Phase Growth, Physical Vapor Transport (PVT), Orientation Patterned ZnSe, infrared countermeasures (IRCM)