Studies of the anisotropic etching of silicon single−crystal wafers and spheres were conducted using 10−M potassium hydroxide as the etchant. The etch rates along the major slow−etch directions were measured. The sides of circular mesas etched into (111), (110), and (100) wafers were found to be inclined to the wafer surface. The angles of inclination varied with azimuthal position and could be correlated with the slow−etch directions measured from an etched sphere. A method was developed to predict these angles of inclination for surfaces of varied orientation using the rate of etching data and angular measurements from an etched sphere.

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Unlike the KNb03-NaNb03 system, the KNbOr AgNb01 system possessed a very limited degree of solid solution between its end-members.Solid solution of AgNbOJ in JCNb03 was limited to slightly less than 6 mole yo, and solid solution of KNb03 in AgNbO3 was limited to less than 0.5 mole yo. Because of a tendency for the K1-,Ag,Nb03 system to lose oxygen spontaneously during firing when 0.06 5 x 5 0.995, the system could not be treated as a true binary system. The compositions in the =boa solid solution region (0 5 x < 0.06) were ferroelectric at room temperature. Lattice parameter, relative permittivity, and thermal expansion measurements were made on specimens in the region 0 < x 5 0.06.of 1040" ?C 2OC for 15 min; the other compositions were fired for 15 min at somewhat higher temperatures. Sintered pellets of compositions selected for property measurements were crushed in a tungsten carbide-faced crusher to -200 mesh, pressed into pellets &/s in. in diameter and l / 4 in. thick, and refired for 15 min at the selected temperatures. Geometrical densities of these sintered ceramic pellets were about 8.5% of theoretical. The KNb03 pellets were pure white; the (&.gsAg0.01)NbO3 was a very light blue, and with increased percentages of silver, this blue coloration increased. The pure AgNbOa was yellow-green. ( 2 ) MeasurementsRelative permittivity (dielectric constant) measurements were made with a General Radio 716-CS1 capacitance bridge at a frequency of 1 Mhz. Silver paste! electrodes were fired onto the specimens a t 760°C. Measurements

Anomalous Hall effects, i.e., peaks in the temperature dependence of the Hall coefficient and Hall mobility, have been observed in liquid-phase-epitaxy (LPE) Hg0.8 Cd0.2Te films. After establishing that surface effects are not the cause of the anomalies and that our LPE films are indeed n type, we propose an inhomogeneity model with a network of extended p-type inclusions in an n-type matrix. Good fits to the experimental data have been obtained by computer simulation based on this model.

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