Daimler-Benz Ag

Temic Telefunken Microelectronic Gmbh

Daimler Chrysler Ag

Andreas Gruhle

Harry Dietrich

Horst Kibbel

Ulf Konig

Hartmut Presting

Heinz-Achim Hefner

Andreas Schuppen

The invention concerns a device for and a process for testing electric motors, in particular fan motors, for functionality, wherein electromagnetic alternating fields produced by an electric motor are received by an antenna, wherein the received signals are analyzed for signal components in the frequency range of the rotation value of electric motors or their harmonics via an analysis unit, and wherein upon determination of functionality the results are indicated by an indicator unit.

Process and device for testing electric motors, in particular fan motors, for functionality

A photodetector which can be operated in two wavelength ranges and is comprised of two detectors (A, B) arranged one on top of the other. A Si Schottky diode forms detector A which absorbs light in a region .lambda.&lt;0.9 .mu.m. Longer-waved light (1 .mu.m&lt;.lambda.&lt;2 .mu.m) is absorbed in detector B which is comprised of an Si/SiGe pn-diode. To increase the efficiency, detector B is made with an integrated resonator. A further increase of the efficiency of the photodetector is accomplished through the mounting of a Bragg reflector on the absorbing layer of detector B.

SiGe photodetector with high efficiency

A process for preparing a bipolar transistor for very high frequencies is described, which is especially advantageous for the preparation of heterobipolar transistors and leads to components with low parasitic capacities and low base lead resistance. The process includes forming a structured first layer with collector zone and insulation areas surrounding the collector zone on a monocrystalline lead layer. A series of monocrystalline transistor layers are grown on the first layer over the collector zone by differential epitaxy and a series of polycrystalline layers is grown at the same time over the insulation areas. A series of polycrystalline layers is designed as a base lead.

Process for preparing a heterojunction bipolar transistor

Manufacture of a semiconductor array of integrated silicon-germanium heterobipolar transistors having a silicon collector layer, a silicon-germanium base layer, a silicon emitter layer and a silicon emitter contact layer includes depositing in a single uninterrupted process and simultaneously doping the collector layer, the base layer, the emitter layer and the emitter contact layer. A base connection region is formed at the side of the base layer such that the intersection surfaces of the base/emitter/PN boundary layer and of the base/collector PN boundary layer with the surface of the semiconductor array are outside the silicon-germanium base layer. A silicon dioxide layer is formed by thermal oxidation over the entire exposed surface of the semiconductor array.

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Ulm, Germany

Andreas Gruhle