S. Middelhoek

Process and design considerations for surface micromachined beams for a tuneable interferometer array in silicon

A special surface micromachining process, using oxidized polysilicon sacrificial layer and poly-nitride/poly membranes, has been developed for realizing the monolithic integration of light modulators with silicon devices. The design and processing considerations for developing a compact micromachined silicon Fabry-Perot interferometer are presented. Initial tests have shown that these micromachined membranes represent a compact and effective light modulating method.<<ETX>>

Surface micromachined tuneable interferometer array

Abstract The development of compact light modulators integrated on the same chip as the signal processing opens many opportunities for combining inter-chip optical communications with standard silicon circuitry. The use of surface micromachining allows high speed of operation and small size integration with other circuitry. The optical and mechanical requirements for the devices also have to be considered, to ensure compatability with standard silicon processing. A surface micromachining process, using an oxide sacrificial layer and poly/nitride/poly membranes, has been developed. This paper presents the optical and mechanical considerations in the development of a compact micromachined silicon Fabry-Perot interferometer. Initial tests have shown that these micromachined membranes represent a compact and effective light modulating method.

Silicon three-axial tactile sensor

Abstract A novel three-axial tactile sensor based on the differential capacitive principle is presented. The sensor is fabricated using IC processing and bulk-micromachining technology. Normal and shear forces are detected by capacitor arrays under force mesas. Experimental devices show sensitivities of 0.13 pF g −1 to normal forces, and 0.32 pF g −1 to shear forces in a force range of 0–1 g. The device has a spatial resolution of 2.2 mm. Its maximum dynamic response frequency is 162 Hz. The force range and sensitivity can be adjusted by changing the membrane thickness. A dynamic measurement range of more than 100 can be obtained using detection circuits with a resolution of 10 fF.

Technology and applications of micromachined silicon adaptive mirrors

The technology of low-cost high-quality micromachined adaptive mirrors is reported. Adaptive mirrors are fabricated by combining bulk silicon micromachining with standard electronics technologies. Mirrors with tens of control channels, having RMS initial deviation from plane of the order of ?/20 and a range of surface deflection of 10 to 20 ?m with linear frequency response in the range of 50 Hz to 1 kHz, are fabricated on standard PCB substrates. Advanced devices with hundreds of control channels, demanding integration of driver and switching electronics, are currently under development

Autocalibration of silicon Hall devices

Abstract A new method for eliminating sensor defects is presented. The autocalibration method uses an on-chip actuator that generates a reference signal to correct the sensor characteristics, ensuring reliable and accurate measurements. Autocalibration also eliminates the need for calibration during manufacturing or during the lifetime of the sensor, which considerably reduces the cost of mass-produced sensors. The on-chip actuator also provides the user with diagnostic information by providing a self-test feature. To illustrate the effectiveness of this method, the principle is successfully applied to a silicon Hall device, which is known for its unstable sensitivity.

Celebration of the tenth transducers conference: The past, present and future of transducer research and development

The aim of this paper is threefold. First, to chronicle the development of the silicon sensor field over the last few decades by briefly discussing the early devices, the technologies, their inventors and the publication dates of their inventions. Second, to provide an overview and an anecdotal history of international Transducers conferences. Third, to predict how silicon sensors and sensor systems might develop in the near future.

Quo vadis silicon sensors

Abstract The silicon-sensor field is more than 25 years old and people are beginning to wonder if silicon sensors will ever achieve the success anticipated at the start of these research activities. In answer to this question, I present an analysis of the present situation in the field of silicon sensors and discuss the markets in which they have a good chance of being more attractive than conventional sensors. I also unfold a strategy for the further successful development of silicon sensors.

Deformable mirror display with continuous reflecting surface micromachined in silicon

A novel micromachined deformable mir- ror display device (DMD) is proposed and character- ized. The principle of operation of DMD differs from that reported in (l). The DMD consists of a freely suspended silicon nitride/Al reflective flexible mem- brane, optical figure of which is controlled electro- statically by the array of integrated electrodes (2, 31. The local curvature of the membrane is proportional to the square of the voltage distribution on the ar- ray of electrodes. The light intensity in the near field of the collimated beam, reflected from the deformed membrane is modulated with the depth of modula- tion being approximately proportional to the mem- brane local curvature. The intensity distribution in the near field of the reflected beam follows approxi- mately the voltage distribution applied to the array of control electrodes. In contrast to (l) the device has 100% pixel fill factor. Contrast ratio of 3 : 1 and resolution of N 100 by 100 pixels with response time of N lms have been demonstrated experimentally.

Microprocessors get integrated sensors: Sensing devices and signal processing built into one silicon chip portend a new class of ‘smart’ sensors

Considers the development of silicon microsensors which can fit on the same chip with a microprocessor. Various sensor types are described, their fabrication presented and their possible applications pointed to.

A 400°C silicon Hall sensor

Abstract The maximum operating temperature of conventional silicon sensors is limited to about 200°C, due to excessive thermal generation of carriers at higher temperatures. The minority-carrier exclusion effect can be exploited to reduce the number of thermally generated carriers, ultimately maintaining extrinsic carrier concentrations at intrinsic temperatures. Based on this effect, a silicon magnetic-field sensor with a maximum operating temperature of about 400°C is presented. The sensitivity has been improved by about 500% with respect to a previously reported version, and now measures about 60 V (A T) −1 at room temperature. Additionally, the theoretical support of the exclusion effect has been improved with a more accurate analytical model.