A novel micromachined silicon displacement sensor based on the conduction of heat between two surfaces through the ambient air is described. A displacement resolution of less than 1 nm and a dynamic range of more than 100 µm was achieved in a 10 kHz bandwidth. To minimize drift, the sensors are operated in pairs, using a differential measurement configuration. The power consumption of these devices is on the order of 10 mW per sensor, and the measured time response is described by a simple exponential with a time constant of approximately 100 µs.

Lattice deformations and misfit dislocations are studied by x-ray double-crystal diffraction and topography for GaInAsP/InP double-heterostructure layers epitaxially grown on (001) InP substrates. No misfit dislocation was observed at the interfaces when the misfits Δa⊥/a between the lattice constants normal to the wafer surface of GaInAsP (0.4 μm thick) and InP layers are within about 5×10−3. The unit cell of the GaInAsP epitaxial layer is tetragonally deformed due to the interface lattice misfit such that the lattice constant parallel to the wafer surface is nearly invariant across the GaInAsP/InP interfaces in the DH wafers both with and without misfit dislocations for ‖Δa⊥/a‖<6.4×10−3.

High quality Ge epitaxial growth has been attained on Si(100) substrates at relatively low temperatures, 350 and 440 °C, by a vacuum evaporation technique. Electrical property and structural quality for the Ge layer were evaluated by Hall measurement, x-ray diffraction, and electron beam diffraction. It is found that the growth layers are p type and that net acceptor concentration and mobility strongly depend on the layer thickness. Of particular significance is the fact that the acceptor concentration decreases most rapidly and hole mobility remarkably increases with the Ge thickness. The acceptor concentration and the mobility at a point larger than 0.7 μm from the lattice mismatched interface are 1.6×1016 cm−3 and 1040 cm2/V sec, respectively. Hole mobility varies as a function of T3/2 and T−3/2 below and above ∼100 °K.

Size, shape, and ordering of SiGe/Si(001) islands grown by means of liquid phase epitaxy under farnonequilibrium growth conditions

The effects of pyrolytic Al2O3 deposition temperature on electrical properties of an inversion-mode InP (MISFET) metal-insulator-semiconductor field-effect transistor were investigated. An Al2O3 gate insulator was deposited using an aluminum isopropoxide organic source on a HCl vapor etched InP surface. An increasing current drift was seen when the insulator was deposited at a temperature below 330 °C. This became exaggerated with decreasing temperature. The observed drift is explained in terms of a time-dependent threshold voltage associated with the polarization of organic molecules or radicals introduced into the insulator by an incomplete decomposition of the source gas during deposition of the dielectric layers at rather low temperatures. The effective electron mobility of the InP MISFET did not show any dependence on the deposition temperature below 350 °C. At higher temperatures, the effective mobility appreciably decreased.