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TUNABLE PRESSURE SENSOR

IP.com Disclosure Number: IPCOM000199450D
Publication Date: 2010-Sep-04
Document File: 6 page(s) / 49K

Publishing Venue

The IP.com Prior Art Database

Abstract

The present invention proposes a tunable pressure transducer based on High Electron Mobility Transistor (HEMT) with two-dimensional electron gas (2DEG) form on a hetero junction of a piezoelectric material. The piezoelectric material combination is an aluminium gallium nitride with gallium nitride (AlGaN/GaN). Pressure applied to the membrane causes necessary strain which modulates conductivity of the 2DEG. The invention offers high temperature, high sensitivity applications, where most of conventional piezo-resistive sensors lose their sensitivity.

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RP13485

BRIEF ABSTRACT

    The present invention proposes a tunable pressure transducer based on High Electron Mobility Transistor (HEMT) with two-dimensional electron gas (2DEG) form on a hetero junction of a piezoelectric material. The piezoelectric material combination is an aluminium gallium nitride with gallium nitride (AlGaN/GaN). Pressure applied to the membrane causes necessary strain which modulates conductivity of the 2DEG. The invention offers high temperature, high sensitivity applications, where most of conventional piezo-resistive sensors lose their sensitivity.

KEYWORDS

    Two-dimensional electron gas (2DEG), Semiconductor pressure transducer, piezo-resistive sensors, High Electron Mobility Transistor (HEMT) structure, pressure sensor, resistance modulation and pinch off voltage

DETAILED DESCRIPTION

    The robust miniaturized pressure sensors find a number of applications in the automotive, aerospace, industrial fields, among others. Basically, piezo- resistive pressure sensors transform a change of the physical quantity pressure into a modulation of sensor's electrical resistance. Over the past years, integrated pressure transducers have been applied on a large scale. However, the contact resistance of the piezo-resistive sensors changes significantly with temperature and masks the changes in sensor signal from actual pressure changes.

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TUNABLE PRESSURE SENSOR

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RP13485

    Therefore there is a need in the art for an efficient pressure sensor which works at higher temperatures and meets high standards for sensitivity, linearity, bursting strength, etc.

    Figure 1 illustrates a High electron mobility transistor (HEMT) structure. The structure consists of compositionally different layers (GaN and AlGaN) grown on a substrate. The different layers form a hetero junction as each layer has a different bandgap. Near the interface of the two layers a two dimensional electron gas (2DEG), the channel, is created. This way it is possible to separate the electrons in the channel from their donor atoms which reduces Coulomb scattering and hence increases the mobility of the conducting electrons. The current flow between two ohmic contacts, source and drain, is controlled by a third contact, the gat...