Honeywell International Inc.

Honeywell G.m.b.h.

Russell L Johnson

Thomas George Stratton

Curtis H Rahn

Kevin D Voegele

A method of forming a piezo-resistive sensor, comprising a piezo-resistor, a leadout resistor, and an insulator structure is provided. A Silicon-On-Insulator (SOI) substrate is provided having an epitaxial layer, a dielectric layer, and a bulk substrate layer. A mask layer is formed on top of the epitaxial layer. The mask layer defines where the piezo-resistor and leadout resistors are to be located by creating first exposed portions of the epitaxial layer. A silicon dioxide layer (SiO) is grown in a Local Oxidation of Silicon (LOCOS) process for a predetermined time on the first exposed portions based on the desired thickness of the piezo-resistor, where the-piezo resistor is located below the SiOlayer. The thickness of the leadout resistor, and therefore the parasitic leadout resistance, is determined by the original thickness of the epitaxial layer and can be maintained independent of the piezo-resistor thickness.

Method and structure of ion implanted elements for the optimization of resistance

A pressure and sensing element is provided that includes one piezo-resistive sensing element configured as a single light implant square, and may produce outputs relating to both a pressure and temperature that has been sensed. The piezo-sensing element may operate as a piezo-resistive radial element when a constant current is conducted through the element in the radial direction with respect to the diaphragm. Conversely, the piezo-sensing element may operate as a piezo-resistive tangential element when a constant current is conducted through the element in the tangential direction to the edge of the diaphragm. A difference in the radial and tangential resistances and a corresponding difference in voltage drop are proportional to an applied pressure, while a sum of the same two resistances is a function of temperature.

Pressure and temperature sensing element

A sensor chip has a piezo-resistive bridge, a temperature resistive bridge, and a multifunctional resistor network that can be used to provide span compensation when operating the piezo-resistive bridge in a constant current mode. In the constant current mode, the multifunctional resistor network can also be used to provide a bias potential to an epitaxial layer of the sensor chip. In a constant voltage mode, the multifunctional resistor network can be used to provide three different gains for a temperature channel that includes the temperature resistive bridge in order to customize the output of the temperature channel for specific operating temperature ranges.

Integrated resistor network for multi-functional use in constant current or constant voltage operation of a pressure sensor

A sensor chip has a piezo-resistive bridge, a first resistor network that can be used for biasing when connected to an external amplifier, a second resistor network that can be used to set gain when connected to the external amplifier, and a leadout resistor that connects an output of the bridge to a common summing point of the two resistor networks. The summing point is connected to the non-inverting input of the external amplifier. The leadout resistor has a predetermined number of squares. A portion of the squares has a light implant and the remaining portion of the squares has a heavy implant. The ratio of the heavy and light implant portions provides customized span compensation of the amplified output for specific operating temperature ranges.

Customized span compensation of SOI pressure sensor

A semiconductor structure includes an upper and a lower layer of semiconductor material separated by a layer of insulation material. Resistors formed in the upper layer are connected into a Wheatstone bridge arrangement having an output. A first voltage provides power to the bridge. A second voltage connected to the lower layer of semiconductor material has a value selected to reduce the drift of the output following power up of the sensor.

Sensor formed on silicon on insulator structure and having reduced power up drift

A measurement system utilizes a sensor formed in a semiconductor on insulator structure that has an offset related to the time that power is applied. A controller applies power, obtains readings and removes power so as to minimize any effect of the offset.

Measurement system utilizing a sensor formed on a silicon on insulator

A temperature compensation scheme for a piezoresistive pressure sensor utilizing resistors with carefully chosen temperature coefficients of resistivity to provide a totally passive network.

Temperature compensation system for piezoresistive pressure sensor

An integrated circuit stress transducer system including signal processing circuitry responsive to signals from semiconductor stress sensors where the processing circuitry output signals are compensated for sensor stress sensitivity variations.

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New Brighton, MN, United States of America

Russell L Johnson