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NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. Muscovite mica, cleaving every 10[Angstroms], provides a crystalline insulator with uniformly parallel surfaces of well known separation ideally suited to the study of electron transport phenomena. Using a micro-splitting technique similar to that developed by Foote and Kazan, muscovite was cleaved in a vacuum of 10(^6) Torr and metal electrodes evaporated, aluminum on one side, gold on the other. The current through 30 and 40[Angstrom] films was measured as a function of voltage and temperature and analyzed in terms of the tunneling theory of Stratton. Using the actual image-force barrier shape, the approximately symmetrical volt-ampere data gave barrier heights of [?] = 0.95 and 0.93eV for the 40 and 30[Angstrom] films, respectively, for an effective mass ratio of m*/m =0.92. The theoretical temperature dependence was observed in the 40[Angstrom] film from room temperature down to liquid nitrogen temperature (77[degrees]K). Thicker films 50 to 10,000 [Angstroms], exhibited temperature dependent volt-ampere curves linear in log I versus [square root of]V over a factor of 10:1 in voltage and a thermal activation energy of 0.55eV, lower than [t]he barrier height above possibly because of injection into polaron states. Preliminary photoelectric response data yielded [?] = 0.8eV, raising some question as to the real meaning of the [?] found from tunneling theory.

A plating technique has been developed that yields extremely uniform metal deposits on semiconductor surfaces. This technique utilizes high field pulses that are extremely short in duration. The technique has produced theoretical Schottky barrier diode spreading resistances for contacts with dimensions ranging from 2.5 to 0.12 micron in diameter. (Author)

The Electronics Research Laboratory of The Aerospace Corporation is developing a heterodyne millimeter wave Superconducting Low Noise Receiver. This report, covering FY 76 and FY76T, discusses the progress in developing techniques to extend the performance of the super-Schottky mixer diode into the millimeter wavelength region. The report is divided into four subjects: (1) the identification of leakage mechanisms and their control; (2) a superconducting Schottky contact to n-type InSb; (3) a superconducting contact to an (InGa)Sb surface on n-InSb, and (4) the contact array diode. (Author)

The incorporation of voltage-tunable reactive elements in microwave monolithic integrated circuits (MMICs) would increase the performance, yield, producibility, adaptability, and affordability of these devices. These improvements would be very important for both low-volume applications, (e.g., space communications) and high-volume applications, (e.g., space-based radar). The feasibility of this concept will be explored by means of the computer-aided design and simulation facilities at The Aerospace Corporation. It is anticipated that some laboratory experiments in selected tuning concepts will be conducted. Tunability would broaden the adaptability of a single design to a wider range of frequency and bandwidth applications. Yield and adaptability relate to the ability to produce chips at an affordable cost.

It is shown that the high frequency performance of mixer diodes can be appreciably improved by employing a Mott barrier instead of a Schottky barrier. The larger junction diameters possible with Mott structures also allow a better burnout capability and improved mechanical stability. (Author)

The contact resistances of gold-GaAs Schottky barriers have been measured at liquid nitrogen temperatures over the range of electron concentrations from 3.2 X 10 to the 18th power to 2.4 X 10 to the 19th power/cc. The theoretical treatment is based on that of Padovani and Stratton but is modified to include Franz's two-band model for the imaginary wave vector of the tunneling electrons and Conley and Mahan's correction to the space-charge potential in degenerate semiconductors. The results correlate well with the theory in the 3.2 X 10 to the 18th power to 5.6 X 10 to the 18th power/cc range of concentrations. The theory must be extended to include the effects of fluctuating depletion width (a suggestion originally made by Bethe) to adequately explain the low contact resistances obserbed with the heaviest doped GaAs. This material is a degenerate and heavily compensated tin alloy regrowth commonly used as an ohmic contact. (Author), Prepared in cooperation with California Inst. of Tech., Pasadena.

The forward current of Schottky barriers on n-type GaAs is investigated as a function of electron concentration in the range of 8 x 10 to the 17th power to 8 x 10 to the 18th power/cc at temperatures from 297 to 4.2K. Both vacuum cleaved and chemically polished surfaces are used. The majority of the junctions studied are gold Schottky barriers, but tin and lead contacts are also examined. The predominant current mechanism is field emission at liquid nitrogen temperature and below for the range of electron concentrations used. These data are in excellent quantitative agreement at 77K with the field emission analysis of Padovani and Stratton of one uses a two-band model for the imaginary wave vector kn. At 297K, thermionic field emission predominates, but for an electron density above 3 x 10 to the 18th power/cc the field emission mechanism with a two-band model still gives reasonable agreement. (Author), Prepared in cooperation with California Inst. of Tech., Pasadena.