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Surface skimming bulk waves (SSBW) in quartz were examined for sensor applications. Sensitivities to substrate strains, temperature, and fluid immersion were determined for AT and BT-cut quartz. The application of a strain sensitive SSBW device configuration as a fluid damped, cantilever beam accelerometer was investigated. This program has resulted in the discovery of an SSAW mode with properties that are extremely well suited to the development of acoustic wave sensors. Originator-supplied keywords include: Surface Skimming Bulk Waves (SSBW), SSBW sensors, and SSBW strain sensitivity.

The reactive rf sputtering technique was applied to the preparation of a wide variety of materials. Single crystal films of ZnO, TiO2, WO3 AlN and GaN were grown on one or more of the insulating crystalline substrates of Al2O3, MgAl2O3, SiC and LiNbO3. Data on the deposition parameters, structure and optical waveguiding characteristics of the heteroepitaxial structures are presented. Reactive sputtering using sublimed arsenic as the sputtering gas inside a heated vacuum chamber was used to grow epitaxial films of GaAs. The controlled growth of single crystal alloys of Ga(1-x)Al(x)As at low temperatures was also demonstrated. Structural, optical and electrical characteristics of these films are presented. Conditions were determined for the deposition of amorphous neodymium ultraphosphate films. Low loss optical wave guide structures were fabricated. Charge storage characteristics of MIS structures were investigated. These employed a composite insulator formed by sputtering 1000A of strontium titanate over a 20A thick thermally grown silicon dioxide layer on silicon., Sponsored in part by DARPA. See also AD0780277.

Fundamental mode bulk acoustic wave resonators and filters have been fabricated from ZnO/Si composite thin films prepared by sputter depositing c-axis oriented polycrystalline ZnO onto single crystal silicon. Resonant frequencies of these devices, which are compatible with silicon IC technology, can be readily controlled in the 100 MHz to 1000 MHz range. Development of improved fabrication procedures is described, emphasizing the importance of smooth resonator surfaces and precise control of ZnO sputtering conditions. Chemical etch treatments of the ZnO is shown to markedly reduce spurious resonances. Device modeling theory is described and the good agreement between experimental data and theory is discussed. Filter insertion loss as low as 4.1 dB and bandwidths between 0.5 and 5 percent have been achieved, Q values as high as 2700 were observed, and out of band rejection of 45 dB was realized. (Author, This article is from the Proceedings of the Symposium on Frequency Control (36th Annual), 2-4 Jun 82, Philadelphia, PA., AD-A130 811, p537-548.

Progress on the process development as it relates to the optical quality of sputtered single crystal films of ZnO, AlN, and TiO2 is discussed. Optical attenuation data for optical waveguide structures comprised of zinc oxide, aluminum nitride, titanium dioxide films grown on sapphire substrates and titanium dioxide on YZ cut lithium niobate is presented. The effect of depositon parameters on the carrier mobility of single crystal gallium arsenide films grown by reactive sputtering is presented., Sponsored in part by DARPA. See also report dated 27 May 1973, AD0760715.

Tunneling in boron doped p-type silicon metal-semiconductor (MS) and metal-insulator-semiconductor (MIS) tunnel junctions has been studied at low temperatures by measuring the derivatives, dI/dV and the second derivative of I with respect to V, of the current-voltage characteristics as functions of applied bias voltage V. Junctions were prepared by evaporating metal contacts onto vacuum or air cleaved silicon surfaces. The general features of the tunneling conductance were found to be in qualitative agreement with existing theories of tunneling in semiconductors. Structure in the derivative data resulting from the interaction of tunneling electrons with silicon zone center phonons and boron local mode phonons has been observed. The optical phonon lineshapes in the most heavily doped MIS units are shown to compare well with the theoretical lineshapes in which modifications in the bulk semiconductor states arising from electron-optical phonon interactions in the semiconductor electrode have been included. The origin of the optical phonon and local mode phonon structure in samples of lower doping is not fully understood. (Author)