D. J. Silversmith

Silicon graphoepitaxy using a strip‐heater oven

Silicon graphoepitaxy has been achieved using a strip‐heater oven and a sample configuration consisting of a relief grating in a SiO2 substrate, a deposited amorphous silicon film, and a deposited SiO2 overlayer or ’’cap.’’ The resulting films are free of cracks and superior in crystallographic orientation and surface smoothness to graphoepitaxial films produced by laser crystallization. Enhancement‐mode, n‐channel, insulated polysilicon gate field‐effect transistors were fabricated and gave surface mobilities of 400 cm2/V sec at a p doping of 1016 cm−3. A SiO2 cap, either intentionally deposited or produced by laser crystallization in the presence of oxygen, was found to be necessary for Si graphoepitaxy. We attribute this effect to shear stresses produced by the SiO2 cap during crystallization.

A Modified Ultrasonic Pulse‐Echo‐Overlap Method for Determining Sound Velocities and Attenuation of Solids

The ultrasonic pulse‐echo‐overlap method described by Papadakis [J. Acoust. Soc. Amer. 42, 1045 (1967)] has been modified to permit simultaneous measurement of the time delay and the relative voltage ratio between any pair of returning echoes in the pulse‐echo train. All the components involved in the present modification are commercially available items, and this instrumentation system for the ultrasonic pulse‐echo‐overlap method is compatible with the pulse superposition method.

A CCD matrix matrix product parallel processor

The design of a CCD matrix-matrix device operating up to 10MHz clock rates, performing the serial-in parallel-out and Fourier transform functions required in radar doppler filtering, will be reported. The chip contains 32 multipliers and 1024 accumulators.

Zone-Melting Recrystallization of Semiconductor Films

The use of zone melting recrystallization (ZMR) to prepare large-grain(and in some cases single-crystal) semiconductor films is reviewed, with emphasis on recent work on Si on SiO 2 . Encapsulants are generally required to minimize contamination and decomposition, induce a crystalline texture,improve surface morphology and prevent agglomeration. In the case of Si, the solid-liquid interface is faceted, which gives rise to subboundaries. These can be entrained by laterally modulating the temperature through the use of an optical absorber on top of the encapsulant. Control of thermal gradients and in-plane crystallographic orientation are important for reliable entrainment.

A 10MHz CCD time integrating correlator

A 32-stage CCD binary-analog time-integrating correlator with a dynamic range greater than 40dB will be described. Time-bandwidth product is 250.