Semiconductor pressure sensor
AssigneeMelexis Technologies SA
InventorAppolonius Jacobus VAN DER WIEL
Life of this patent
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Abstract
A semiconductor pressure sensor for measuring an external pressure exerted on the sensor, comprises: a membrane; a first resistor connected between a first bias node and a first output node; a second resistor connected between said first bias node and a second output node; a first and second current source connected to the first resp. second output node for generating a differential voltage signal indicative of the external pressure to be measured. The resistors comprise piezo-resistive strips arranged in particular crystallographic directions. The circuit may have a third and four resistor pair for compensating package stress. The Piezo-resistive strips may be formed as p-doped regions within an n-well, the biasing node being electrically connected to the n-well.
Claims15
A semiconductor pressure sensor for determining an external pressure exerted on the sensor, comprising:
- a membrane as part of a semiconductor substrate for being deformed due to the external pressure, having a membrane edge and a membrane thickness;
- a first resistor pair located on or adjacent to a first side portion of the membrane, the first resistor pair comprising a first resistor connected between a first bias node and a first output node, and a second resistor connected between said first bias node and a second output node different from the first output node, the resistance of the second resistor being equal to that of the first resistor;
- a first current source connected or connectable to the first output node and adapted for causing a first predefined current to flow through the first resistor so that the first output node assumes a first output voltage;
- a second current source connected or connectable to the second output node and adapted for causing a second predefined current to flow through the second resistor so that the second output node assumes a second output voltage, wherein the second predefined current is substantially equal to the first predefined current;
- the first resistor comprising one or more first elongated piezo-resistive strips arranged in a first direction for measuring deformation of the membrane due to the external pressure to be measured, the second resistor comprising one or more second elongated piezo-resistive strips arranged in a second direction for measuring deformation of the membrane due to the external pressure to be measured, wherein the second direction is substantially perpendicular to the first direction;
- the first and second output voltage forming a first differential voltage signal indicative of the external pressure to be measured.
A method of determining an external pressure exerted on a semiconductor substrate, the semiconductor substrate comprising:
- a membrane arranged for being deformed due to the external pressure, and having a membrane edge and a membrane thickness;
- a first resistor pair located on or adjacent to a first side portion of the membrane, the first resistor pair comprising a first resistor connected between a first bias node and a first output node, and a second resistor connected between said first bias node and a second output node different from the first output node, the resistance of the second resistor being equal to that of the first resistor;
- the first resistor comprising one or more first elongated piezo-resistive strips arranged in a first direction for measuring deformation of the membrane due to the external pressure to be measured, the second resistor comprising one or more second elongated piezo-resistive strips arranged in a second direction for measuring deformation of the membrane due to the external pressure to be measured, wherein the second direction is substantially perpendicular to the first direction;
- the method comprising the steps of:
- connecting a first current source to the first output node, the first current source being adapted for causing a first predefined current to flow through the first resistor so that the first output node assumes a first output voltage;
- connecting a second current source to the second output node, the second current source being adapted for causing a second predefined current to flow through the second resistor so that the second output node assumes a second output voltage, wherein the second predefined current is substantially equal to the first predefined current;
- obtaining a first differential voltage signal over the first and second output node as an indication of the external pressure to be measured.
Dependencies are inferred from the claim text.