*** ABSTRACT 9661323 Vernon This Small Business Innovative Research Phase I project will develop an innovative, high-pressure metalorganic chemical vapor deposition (MOCVD) reaction chamber for improved growth of Group-III nitrides. Growth at pressures above one atmosphere will increase cracking efficiency of ammonia, limit material desorption, lower the density of nitrogen vacancies, and lead to better crystal quality by permitting higher temperature growth. Phase I will demonstrate growth of GaN using a high-pressure MOCVD reaction chamber, operating up to ten-atmospheres pressure. The chamber will be a vertical, inverted-flow design to minimize convection. MOCVD growth of the first GaN laser diode at Nichia used a configuration which simulates high pressure with a "push" flow orthogonal to the growth stream. At Spire, high-pressure MOCVD has been successfully employed for InP growth using substantially less phosphine than normally required. In fact, InP with specular surfaces and good crystal quality has been deposited at three atmospheres with a V:III ratio of 1:1, the lowest ratio ever reported for the successful growth of InP. Phase II will develop growth parameters for GaN, InGaN, and AlGaN device structures. Process optimization will include use of nitrogen in the carrier gas to better confine heat to the wafer surface by reducing thermal conductivity. The market potential for GaN is tremendous, especially in optical storage (blue lasers and LEDs) and high-temperature electronics. Products made from this material system are already in large demand. If successful, high-pressure MOCVD may be the process of choice for GaN growth. Spire will offer high-pressure reactors to device manufacturers, while we use this technology to expand our optoelectronics epitaxial service business to include structures for shorter-wavelength devices. ***
