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Increased purity, improved electrical properties, lower net carrier concentration, and higher mobilization obtained for single crystal gallium phosphide solar cell by using chloride transport
Vapor deposition and acceptor impurity diffusion techniques are used to prepare indium-gallium phosphide junctions. Certain problems in preparation are overcome by altering gas flow conditions and by increasing the concentration of phosphine in the gas. A general formula is given for the alloy's composition.
Metallurgical, electrical, and optical properties of gallium phosphide crystals
Barrier diodes formed by nickel evaporation on undoped gallium phosphide by vertical liquid epitaxy
Preparation of ohmic contacts from alloying germanium and gallium phosphide
Preliminary results are reported on the development of a high temperature (350 C) gallium phosphide bipolar junction transistor (BJT) for geothermal and other energy applications. This four-layer p(+)n(-)pp(+) structure was formed by liquid phase epitaxy using a supercooling technique to insure uniform nucleation of the thin layers. Magnesium was used as the p-type dopant to avoid excessive out-diffusion into the lightly doped base. By appropriate choice of electrodes, the device may also be driven as an n-channel junction field-effect transistor. The initial design suffers from a series resistance problem which limits the transistor's usefulness at high temperatures.
Summary information on various studies to determine metallurgical, electrical, and optical properties of gallium phosphides
Optical, electrical, and metallurgical properties of GaAsP alloy system and GaP related to their use as semiconducting materials
Schottky barrier diode performance tests, Be doping of GaP, and S, Se, and Te diffusion into GaAs
Optical absorption spectra of Ni impurity in GaP due to d shell transitions, measuring crystal field parameters, noting fine structure
Depth and planarity of zinc diffused junctions in GaP using temperature, phosphorus overpressure and time as independent variables
Schottky barrier diodes for high temperature operation prepared on n type GaP single crystals, studying I-V and C-V characteristics
Development of high reverse breakdown voltage and low forward voltage drop stability in high power Schottky GaP rectifier for high temperature application is reported.
Large area high performance, GaP rectifiers were fabricated by means of Zn diffusion into vapor phase epitaxial GaP. Devices with an active area of 0.01 sq cm typically exhibit forward voltages of 3 volts for a bias current of 1 ampere and have reverse breakdown voltages of 300 volts for temperatures from 27 C to 400 C. Typical device reverse saturation current at a reverse bias of 150 volts is less than 10 to the minus 9th power amp at 27 C and less than 0.000050 amp at 400 C.
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High temperature (300 C) diodes for geothermal and other energy applications were developed. A comparison of reverse leakage currents of Si, GaAs, and GaP was made. Diodes made from GaP should be usable to 500 C. A Liquid Phase Epitaxy (LPE) process for producing high quality, grown junction GaP diodes is described. This process uses low vapor pressure Mg as a dopant which allows multiple boat growth in the same LPE run. These LPE wafers were cut into die and metallized to make the diodes. These diodes produce leakage currents below ten to the -9th power A/sq cm at 400 C while exhibiting good high temperature rectification characteristics. High temperature life test data is presented which shows exceptional stability of the V-I characteristics.
In the vapor phase epitaxy fabrication of semiconductor devices and in particular semiconductor lasers, the deposition body on which a particular layer of the laser is to be grown is preheated to a temperature about 40.degree. to 60.degree. C. lower than the temperature at which deposition occurs. It has been discovered that by preheating at this lower temperature there is reduced thermal decomposition at the deposition surface, especially for semiconductor materials such as indium gallium phosphide and gallium arsenide phosphide. A reduction in thermal decomposition reduces imperfections in the deposition body in the vicinity of the deposition surface, thereby providing a device with higher efficiency and longer lifetime.