9526483 Miller The goal of this project is to investigate and develop III-V semiconductor-based optoelectronic emitters, detectors, and electronic circuits with improved performance. The approach focuses on an important materials issue which affects many present devices and integrated optoelectronic circuits: controlled heavy p-type doping in an epitaxial structure, using carbon. Gaseous, carbon tetrabromide, CBr4 will be used for carbon doping in solid source molecular beam epitaxy (MBE). Stable, low-resistance p-type contacts, improved laser lifetime, and improved heterojunction bipolar transistor (HBT) reliability will be developed and demonstrated. The common p-type dopant for solid-source MBE is Be. At doping concentrations exceeding about lxlO^19/cm3, Be can diffuse rapidly during epitaxial growth and also during device operation. This phenomenon makes it difficult to grow high-performance microwave HBTs with good yield and reproducibility using Be, and also leads to a rapid degradation in device performance. As a result, commercial suppliers of epitaxial material grown by MBE find it virtually impossible to sell wafers for use in HBTs. There is also evidence that a similar phenomenon limits the performance of lasers grown with Be. The use of carbon rather than Be in solid-source MBE growth will reopen the growth of high reliability, highly p doped, high performance devices to this technique. The approach of this project is to use carbon tetrabromide, CBr4, for p type doping in solid-source MBE growth. The project couples the growth by MBE of AlGaAs, GaAs, AlInAs, and GaInAs materials on GaAs and InP substrates closely to the design, fabrication, and testing of HBTs, lasers, and detectors. This is an extension to optical emitters, detectors, and device reliability of the principal investigators' prior work on CBr4 doping. ***
