Abstract: The concentration of internal gettering sites within a semiconductor wafer is controlled by two-step thermal processing. In a concentration reduction phase, the wafer is rapidly heated to an elevated temperature in the range from about 900.degree. to 1350.degree. C., resulting in the partial or total dissolution of precipitable impurities within the wafer. In a concentration enhancement step, the wafers are subjected to a relatively low temperature anneal process where the density of potential internal gettering sites is increased. By properly controlling the processing temperatures and treatment times, the two steps may be performed in either order to obtain wafers having internal gettering site concentrations within a desired range.

Abstract: For the identification of defects in a non-structured surface, the surface to be investigated scanned with a scanning light ray wherein the light scattered and defracted by a defect is collected on a light sensitive surface of an opto-electronic receiver. In order to also be able to detect defects in a submicrometer range, a diaphragm for reducing the scattered light components in the scanning light ray prior to reaching the surface being tested is provided in the path of the scanning ray and has at least two diaphragm edges which are successively arranged in the diaphragm so that they respectively block out or cover only the shadow region of the preceding diaphragm edge. The test installation is particularly useful in testing a mask which has not yet been structured.

Abstract: A method and an arrangement for detecting error signals in a magnetic disk drive apparatus uses a test disk which has a plurality of test tracks distributed over the recording area and containing special test signals, a distinction being made between orientation, adjustment and azimuth bursts. Based on the normal position of the recording tracks of the magnetic disk, the spacing of the test tracks could depend on the type of step motor if such a motor is used in the positioning device. By special control, hysteresis errors can be measured in addition to tracking errors, eccentricity errors and azimuth errors.An advantageous use is for all types of disk drives, preferably FlexyDisk drives.

Abstract: An end cap for a windshield wiper motor housing includes a cylindrical shell and an end cap, the end cap being retained on the shell without fasteners. This is achieved by placing the end cap within the shell in a prestressed condition and forming supporting elements on one side of the end cap and holding elements on the other side of the end cap. The supporting and holding elements are axially spaced from each other by an amount less than the thickness of the material of the rim of the end cap so that the rim of the end cap in the finished configuration has a corrugated contom. The forces exerted on the holding and supporting elements by the elasticity of the end cap material effectively prevent the end cap from turning relative to the shell and makes the shell more shock resistant.

Abstract: A mixing apparatus utilizes piston burettes driven by stepping motors as metering pumps to deliver component liquids to be mixed into a liquid stream in a selectable constant mixing ratio. A computer-based automatic control system is used to control the regulated take up of the respective components by the burettes and the delivery of them to a mixing device. The computer calculates the rates of stepping of the respective motors so that each component is delivered over the same period of time and at a respective uniform rate. The computer also controls associated switching valves via an interface device and may be a desk top machine with keyboard or pre-programmed data input.

Abstract: At the end of a downwardly slanted track, a duct of S-shaped cross section is provided to receive tubes and rods. The duct wall members are cushioned and can be tilted apart; belts are disposed across the bottom of the duct and are gradually released to form receiving loops which increase in size accordingly, for holding and bundling the tubes or rods.

Abstract: A process for the analysis of aqueous solutions, in which the sample is introduced into a stream of liquid color reagent and the reaction product formed in a chromatogaphic column under pressure is measured in a suitable detector.