Atomic and electronic structure of InP-metal interfaces: A prototypical III-V compound semiconductor Intrinsic and extrinsic interface states at lattice matched interfaces between III-V compound semiconductors: The InAs/GaSb(110) system J.Surface photovoltage spectroscopy (SPS) has been used for direct measurements of the extrinsic surface states within the band gaps ofp-InP ( 110) and ( 100) and n-GaAs( 110) before and after Al and Au deposition. The observed metal-induced surface states are found to pin the Fermi level at monolayer coverages at E,, + 0.83 eV for Au/p-InP( 1 lo), E, + 1.10 eV for Al/p-InP( 1 lo), EC -0.94 eV for Au/n-GaAs( 1 lo), and EC -0.80 eV for Al/n-GaAs( 110). The Au/Al/p-InP( 110) structure, studied for the first time using SPS provides evidence of strong Al clustering upon the InP surface. Chemically etched and UHVcleavedp-InP surfaces and Au interfaces are also compared. The correlation between the observed energy state positions and electrically measured Schottky barrier heights is discussed.

Complex monolithic Si MEMS can be created using a single mask by extending the empty-space-in-silicon (ESS) or silicon-on-nothing (SON) technology. The fabrication combines isotropic and anisotropic etching with selective removal of passivation layers followed by hydrogen annealing. The resulting expanded design space includes multilayer structures and embedded cavities. The MEMS formation by the hydrogen annealing is simulated both at large scales and microscopic scales that together predict the shape of the finished MEMS. We demonstrate the accuracy of our process and simulations by fabricating single-and double-layer evacuated silicon voids that form Fabry-Perot optical pressure sensors with the sealed voids as pressure references. We also create multi-layered sensors with an integrated photonic crystals sensing diaphragm for improved optical readout. The sensors have a calculated 6.7 µV/Pa sensitivity and low noise over a dynamic range of over 70.9 kPa.

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Surface photovoltage spectroscopy has been used in order to investigate surface states at Al/n-GaAs (110), Au/n-GaAs (110) and Al/p-InP (110), Au/p-InP (110),(100) interfaces. Our results show formation of metal-induced surface states, which can be correlated with Fermi level pinning positions. The observed energy positions are found to be in good agreement with electrically measured Schottky barrier heights. The results obtained for these metals and the different surface types are discussed and compared to published data.

We have investigated a method for passivation of InSb by vacuum deposition of SiO x on native oxide layers grown by wet anodization. We show that this multilayer dielectric approach results in improved passivation properties. Results of high resolution Auger spectroscopy reveal important information on the layer structure and composition of this passivation film. Specifically, we report the experimental observation ofSi0 2 formation at the SiO x anodic oxide interface. The interfacial reaction is limited to a thin layer, about 10 nm thick. The SiO x oxidation proceeds by reduction of the native oxide and formation of elemental In and Sb. The electrical features observed in the C-V curves (such as flat-band voltage, hysteresis, low-frequency-like response in the inversion region, and other deviations from the ideal curves) are explained in view of the oxidation states of In and Sb, observed at the oxide layers and at their interfaces. These correlations were used for characterization' of the desired interlayer parameters.