9315998 Wicks This proposal concerns an advance in the technology of molecular beam epitaxy (MBE) that the solves the earlier difficulties with the use of solid phosphorus sources and enables the phosphine-free (and arsine-free) growth of phosphorus containing materials of quality at least equal to those of the gas source techniques. Specifically, it is proposed to further preliminary results obtained on the use of solid charges of phosphorus in valved effusion cells for the growth of phosphides, and to extend this approach to the use of solid phosphorus and arsenic valved effusion for the growth of arsenide/phosphide alloys and arsenide/phosphide heterojunctions. The project will be a comprehensive study of the influence of solid source MBE growth parameters (growth temperature, beam fluxes, duration of growth interruptions at interfaces, group V dimer vs. tetramer species, different vendors of phosphorus, etc.) on materials characteristics. Materials characteristics will be evaluated with a variety of electrical and optical measurements. The ultimate characterization of materials will be the performance of the materials in devices, such as diode lasers (AlGaInP/GaAs and GaInAsP/InP) and heterojunction bipolar transistors. Most of these materials and device characterizations will be done in-house, however a significant amount of collaboration will occur with researchers from other universities and industrial research laboratories. A second aspect of the project is concerned with MBE hardware issues such as pumping; dealing with flammable deposits in the MBE machine; and beam control, stability, and switching. Iterations on hardware configurations and designs will be required to optimize the operation of the system with solid phosphorous sources. Success in this proposed program would establish that valved, solid source MBE has equivalent (or perhaps even superior) capabilities to those of gas source MBE (GSMBE) and organometallic vapor phase epitaxy (OMPVE), thereby eliminating th e need to use arsine and phosphine. The resulting improvements in safety and cost would benefit those already in the important field of phosphorous-containing semiconductors, and open up the field to those who are not presently willing or able to use toxic gases. ***
