Integrated Pressure Sensor Research Articles

Microsensor techniques for cardiovascular systems

Summary. Progress in semiconductor technology has been very fast in the last few years. One important fabrication process is the CMOS (Complementary Metal Oxide Semiconductor) process. This technology has been developed for the fabrication of electronic circuits, but is now also used for the fabrication of microsensors and microsystems by adding some compatible process steps. This contribution reports upon some examples for the application of CMOS-compatible physical microsensors with on-chip integrated read-out electronics in a cardiovascular ambient. Especially monolithically integrated pressure sensors and flow sensors for blood pressure and blood flow measurement are presented, representing the state-of-the-art techniques of CMOS-compatible surface micromachining and bulk micromachining. Due to the flexible design possibilities, the surface micromachined pressure sensor with a chip size of 0.7 mm × 7 mm or even smaller can be placed in a heart catheter with a diameter of 1 mm for blood pressure measurement in arterial vessels. Additionally a temperature sensor is integrated on the chip. In the same catheter application a flow sensor chip based on a hot-film anemometry principle measures blood flow dynamically with a fast response and low power consumption combined with small dimensions. A system with integrated circuits used for data acquisition with wireless data transfer of cardiovascular sensor signals from inside the body is also discussed.

Low-cost high-sensitivity integrated pressure and temperature sensor

Abstract A resistive temperature detector along with a capacitive pressure sensor using a silicon membrane have been integrated on a glass substrate. The metrological characteristics of this miniaturized sensor feature a pressure sensitivity of 1.29 pF/bar between 1 and 6 bar and a temperature sensitivity of 6200 ppm/°C between −40 and +130 °C. In the pressure and temperature ranges considered, the main cause of error is non-linearities that generate imprecisions less than or equal to ±3% of the full scales. The technological process allows these new devices to be batch produced.

Piezojunction effect based pressure sensor

The Letter describes a method for fabricating integrated pressure sensors based on the piezojunction effect. Localised stress concentration is realised via a micromachining-fabricated needle-like structure, which is an integral part of the diaphragm. Such a stress concentrator emulates the previously used hard stylus. Owing to the absence of any friction, a reliable and hysteresis-free output was obtained.

A novel structure of pressure sensors

A structure for discrete and integrated pressure sensors is proposed. A piezoresistive bridge pressure sensor and a pressure-sensitive MOS oscillator on this structure were fabricated and tested. The fully MOS-compatible technology, high-grade performance, intrinsically low temperature coefficient, and feasibility of fabrication are described to show the advantages of the new structure for production of discrete and, in particular, integrated pressure sensors and large-area sensor arrays. >

A novel pressure sensor structure for integrated sensors

A novel pressure sensor ‘silicon box’ structure is proposed, fabricated by one-sided processing technology. Tests and analyses show that, while the excellent performance of single crystal silicon diaphragm sensors is maintained, the new technique has advantages for both discrete and integrated pressure sensors of high yield, good uniformity, low cost and feasibility of mass production. This structure also provides some reduction of thermal stress caused by the mismatch between the chip and the substrate occurring in a silicon cup structure.

One-chip integrated pressure sensor

One-chip integrated pressure sensor

ワンチップ集積化圧力センサ

ワンチップ集積化圧力センサ

Semiconductor dynamic sensors

Various sensors of dynamic quantities, whose principle is based on the piezoresistive effect of semiconductor silicon, are overviewed. After a brief description of the fundamentals of silicon strain gauges and semiconductor pressure sensors, some applications of these basic sensors to a ball load cell and a microsized acceleration sensors are presented. Currently developed integrated sensors fabricated by micromachining technique are classified into two types: (1) sensors with both a sensor part and an electronic circuit, such as integrated pressure sensors; (2) multiple sensors formed on one substrate, such as a multi-vibration sensor. The future development of sensors is discussed in connection with these integrated sensors.

Nonlinear analysis of a CMOS integrated silicon pressure sensor

This paper reports theoretical and experimental results of analysis on the nonlinear characteristics of a CMOS integrated pressure sensor with a square silicon diaphragm. It is shown that nonlinearity is caused by both the large diaphragm deflection and the nonlinear piezoresistance of the resistors. The optimum layout for the piezoresistors to minimize their nonlinearity is also shown. The measured nonlinearity for the fabricated device agrees well quantitatively with the numerically analyzed nonlinearity.

A piezoresistive integrated pressure sensor

A silicon piezoresistive integrated pressure sensor (IPS) containing sensing, temperature compensation and amplification circuits has been developed for automotive and industrial applications, etc. The chip of the IPS is bonded on a silicon support 2 mm thick, using an electrostatic bonding technique for reducing unwanted thermal stress from the support and package. Temperature invariant and laser trimmable printed thick film resistors for adjusting temperature compensation and Transfer function scaling are formed on the ceramic plate around the IPS chip, which is then mounted in a modified TO-3 package as a three terminal device. Experimental results and simulations of span temperature compensation in the sensing element bridge and the fully assembled IPS are shown here to be in good agreement. The temperature dependence of the zero and non-linearity of the IPS are also described.