Sensor element for thermal anemometry
AssigneeRobert Bosch GmbH
InventorsFlorian Schoen, Christian Lemier, Torsten Kramer
Life of this patent
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Abstract
A sensor element for thermal anemometry includes a semiconductor substrate and a thin-film diaphragm attached to the semiconductor substrate and having a front side and a rear side. A resistive heating element and a temperature-dependent resistor are attached to the front side of the thin-film diaphragm. In the area of the rear side of the thin-film diaphragm, the semiconductor substrate has a first recess. A silicon layer including a recess which merges with the first recess of the semiconductor substrate is located between the thin-film diaphragm and the semiconductor substrate.
Claims8
A sensor element for thermal anemometry, the sensor element comprising:
- a semiconductor substrate;
- a film diaphragm attached to the semiconductor substrate;
- a resistive heating element on a front side of the film diaphragm;
- a temperature-dependent resistor on the front side of the film diaphragm;
- a silicon layer between the film diaphragm and the semiconductor substrate, wherein a first recess, which is in the silicon layer, merges with a second recess, which is in the semiconductor substrate at a rear side of the film diaphragm;
- a first silicon oxide layer between the silicon layer and the semiconductor substrate;
- and
- wherein the film diaphragm includes a second silicon oxide layer formed in one piece with the first silicon oxide layer.
A sensor element for thermal anemometry, the sensor element comprising:
- a semiconductor substrate;
- a film diaphragm attached to the semiconductor substrate;
- a resistive heating element on a front side of the film diaphragm;
- a temperature-dependent resistor on the front side of the film diaphragm;
- a silicon layer between the film diaphragm and the semiconductor substrate, wherein a first recess, which is in the silicon layer, merges with a second recess, which is in the semiconductor substrate at a rear side of the film diaphragm;
- in an area of the first recess, a first silicon oxide layer coating the silicon layer;
- and
- wherein the film diaphragm includes a second silicon oxide layer formed in one piece with the first silicon oxide layer.
An air mass flow meter comprising:
- a sensor element for thermal anemometry, the sensor element including:
- a semiconductor substrate;
- a film diaphragm attached to the semiconductor substrate;
- a resistive heating element on a front side of the film diaphragm;
- a temperature-dependent resistor on the front side of the film diaphragm;
- a silicon layer between the film diaphragm and the semiconductor substrate, wherein a first recess, which is in the silicon layer, merges with a second recess, which is in the semiconductor substrate at a rear side of the film diaphragm;
- and
- a first silicon oxide layer between the silicon layer and the semiconductor substrate;
- wherein the film diaphragm includes a second silicon oxide layer formed in one piece with the first silicon oxide layer;
- an activation circuit for electrically heating the film diaphragm using the heating element;
- and
- an evaluation circuit for determining a temperature of the film diaphragm using the temperature-dependent resistor.
Dependencies are inferred from the claim text.