Schlumberger Industries

Centre National De La Recherche Scientifique

Schlumberger Industries, Sa

Jean-Louis Robert

Vincent Mosser

Sylvie Contreras

Julien Pernot

Jean Camassel

A metrological Hall effect sensor with sensitivity to temperature less than 250 ppm/&deg; C. and with high Hall effect coefficient for temperatures greater than 200&deg; C. formed in a multilayer structure comprising a thin active layer deposited on a substrate, wherein the substrate is made of monocrystalline silicon carbide (SiC), and wherein the thin active layer is made of a weakly type n-doped silicon carbide (SiC) semiconductor in the exhaustion regime.

Hall effect sensor

A Hall effect sensor of two-dimensional electron gas type comprising, on an insulating substrate, a quantum well structure, a carrier injection layer adjacent to the quantum well structure, of thickness less than 250 .ANG. and having an density per unit area of donors integrated over the whole thickness of the carrier injection layer less than 5.times.10.sup.12 cm.sup.-2, an insulating burial layer deposited on the carrier injection layer, having a conduction band with an energy level greater than the Fermi energy of the sensor and a thickness greater than 200 .ANG.. Applicable to the field of electricity meters and current sensors.

A monolithic pressure and/or temperature transducer comprises at least two sensitive semiconductor layers of III-V material sensitive to pressure and to temperature and supported by a common substrate of III-V material, which two layers comprise: a first layer doped with donor type impurities at a first concentration and having a first resistivity as a function of pressure and of temperature; and a second layer doped with donor type impurities at a second concentration different from the first concentration and having a second resistivity as a function of pressure and of temperature, which second resistivity depends on temperature in a different manner than the first resistivity.

Hydrostatic pressure transducer

Solid state pressure sensors based upon aluminum gallium arsenide devices are disclosed. One embodiment uses a TEGFET as a hydrostatic pressure sensor. By adjustment of the gate voltage, it is possible to vary the operating conditions of the sensor, so as to adapt it dynamically to particular measurement conditions. Another hydrostatic pressure transducer, essentially made from aluminum gallium arsenide on a gallium arsenide substrate, comprises a layer sensitive to pressure and a layer sensitive to temperature: due to its homogeneous structure and its rigorous temperature compensation, this transducer offers both high accuracy and high sensitivity.

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Le Cres, France

Jean-Louis Robert