The Naval Research Laboratory currently produces high purity, low defect, one inch diameter monocrystal GaAs by the liquid encapsulated vertical zone melting technique (LEVZM) in a specially designed quadrant controlled Q-EDG furnace developed by the Mellen Company, Inc. The unique feature of their present Mellen furnace is its ability to precisely control the local heat flow characteristics within the molten zone in the axial, azimuthal, and radial directions (3d). In Phase I, Mellen used a larger, 5" diameter Q-EDG furnace, modified to include a "stealth" heater, to mechanically and thermally test the feasibility of 3-4 inch diameter growth. Tests indicate that success is within our grasp. General design and testing of the proposed new furnace for use in a manufacturing environment to produce 4" dia. high purity, single crystal GaAs as bulk material have been completed in Phase I. Phase II of this work, proposed herein, discusses the thermal and mechanical considerations cited in the Phase I final report along with a work plan to build the furnace and then test these new concepts under Phase III. A combination of proprietary existing EDG technology and proprietary new technology is utilized in this proposal to overcome the thermaland mechanical requirements of this LEVZM process. Anticipated benefits/
Potential Commercial Applications: The LEVZM growth technique used in conjunction with a modified quadrant controlled EDG furnace system will be able to consistently produce 3" to 4" diameter single crystal boules of GaAs. The process developed may be applied toward growing other III-V and II-VI semiconductor single crystal materials.
