The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
We report on a 32-MHz quartz TCXO fully integrated with commercial CMOS electronics and vacuum packaged at wafer level using a low-temperature MEMS-after quartz process. The novel quartz resonator design provides for stress isolation from the CMOS substrate thereby yielding classical AT-cut f/T profiles and low hysteresis which can be compensated to < ± 0.2 ppm over temperature using on-chip third-order...
The proposed MEMS-technology viscosity sensor solves two major drawbacks associated with current state of the art MEMS viscosity sensors, such as: (1) Functional complexity and integration of external components for actuation and subsequent data acquisition; (2) Fabrication incompatibilities with CMOS processes. The proposed solution is based on thermally induced actuation, subsequent vibrations of...
In this work, we propose a novel temperature compensation method that utilizes a tri-mode operation scheme to generate a temperature-stable frequency reference over a large temperature range. Three resonant modes are excited simultaneously on a highly doped silicon MEMS resonator, and the unique TCf characteristic of each mode is fitted to a parabolic curve. A linear combination of the three frequencies...
This paper reports a method of measuring the on-chip thermal stress for silicon resonant accelerometer (SRA). This method could be used to evaluate the stress-temperature characteristic of SRA, and that would help to focus the problems exist in SRA. Clamp-clamp Double Ended Turning Fork resonator is used as a basic measurement unit. Analysis of the accuracy and noise in stress measurement is given...
On-chip integration of quartz resonators with Si devices opens new opportunities for microsystem miniaturization and enhanced performance. In addition to integrating with electronics, the integration of piezoelectric quartz resonators with other sensors of different material composition is also possible. In this paper, we demonstrate that a VHF SC-cut quartz resonator can be integrated within a high-aspect-ratio...
Two kinds of new silicon actuators, cantilever and twisted-beam, based on pn diode actuation principle are presented. The space gap that is absolutely needed in conventional electrostatic MEMS actuators is replaced by a depletion layer in reversely-biased pn diode. The strong electric field generated in the depletion layer forces a silicon microstructure to vibrate. The microstructure causes a large...
In this work, a MEMS infrared source applied to compact Non-Dispersive Infrared (NDIR) gas sensor is reported. Compared to other related things, the source coats integrated nanostructure black silicon compatible with CMOS technique on the poly-silicon. Hence the emissivity is as high as 98% at 3∼5µm wave range; relat ively the radiation efficiency is increased by 40% through calculation. Suspension...
This work presents a micro-ovenized 77.7 MHz silicon MEMS oscillator using resonator's structural resistance as an embedded temperature sensor. The structural resistance of a silicon microresonator exhibits a large temperature coefficient of resistance (TCR) and is used as a sensitive self-temperature sensor to accurately and locally monitor resonator's temperature. A novel cross-sectional Lamé-mode...
This paper reports a packaged MEMS capacitive pressure sensor based 3C-SiC using bulk-micromachining technology that operates on the pressure up to 5.0 MPa and temperature up to 500 ºC. The diaphragm employs a single-crystal 3C-SiC thin film that is back-etched from its Si substrate. A photosensitive ProTEK PSB is used as a protection mask layer to reduce the process steps. We compare our results...
We report quartz level temperature stability of piezoelectrically driven silicon MEMS resonators. Frequency stability of better than ±10 ppm is measured for 23 MHz extensional mode resonators over a temperature range of T = −40 … + 85°C. The temperature compensation mechanism is entirely passive, relying on the tailored elastic properties of heavily doped silicon with a doping level of n > 1020...
This paper gives a detail description of a silicon vibration beam accelerometer which was fabricated by SOI technology and encapsulated in a wafer level vacuum package. The wafer level package gives advantage of small size and low cost, but also produce additional residual stresses that increased the temperature coefficient of the vibration beams. To solve this problem, the sensing structure was redesigned...
In this work, an oxide-refill process is used to null the first-order temperature coefficient of frequency (TCF) of silicon MEMS resonators and to achieve high thermal resistance isolation structures. The technology enables fabrication of a low-power ovenized micro-platform on which multiple MEMS devices can be integrated. The intrinsic frequency-temperature characteristic of two resonators is utilized...
In order to clarify the source of resonant frequency drift in MEMS resonators, thermal expansion effect of packaging on MEMS devices was investigated. The strain in a silicon plate bonded on an aluminum plate with temperature was precisely measured. Increasing amount of strain in the aluminum plate was as large as 200 micro-strain with increase in only 20 degrees of temperature. The strain in the...
In order to excite silicon microcantilevers under the temperature ranging from room temperature to 500°C, an impact base excitation device was developed. In excitation device, an electric heating plate is used as the heating element to heat the testing microstructure. A separated structure was designed to protect the piezoelectric ceramic apart from the damage due to the high temperature. Using the...
Micro electromechanical system (MEMS) is an emerging technology that gives high accuracy and high speed with least error due to the micro dimension. To design a simple but accurate MEMS sensors remains a challenge. Modeling of a MEMS temperature sensor, using simple microcantilever structure, is represented in this paper. The sensor is actuated electrostatically. The effect of temperature on the resonance...
The MEMS Si thermal convective inclinometer without solid proof mass has many advantages such as more robust and immune to vibration shocks compared with traditional inclinometer. In this paper, a 3D parametric model of this kind of inclinometer has been setup. The influences of different airflow velocity under high environmental temperature have also been considered to study how they affect the sensitivity...
Warpage is one of the challenging problems for wafer level package (WLP). Especially, the bonding process of multiple wafers will bring additional stress to WLP and warpage of WLP. This paper aims at the stress and warpage characteristics of the WLP (consisting of silicon cover wafer and silicon MEMS wafer) with glass frit bonding. The finite element (FE) method and MOS (Multi-beam Optical Sensor)...
The working principle and fabrication process of MEMS density sensor have been studied in this paper. And the density experiments were performed in acetone and silicon oil at temperatures in the range from 20.0 to 50.0 °C under atmospheric pressure. The maximum deviation and the average absolute deviation between the density experimental results and the reference values are −0.72% and 0.32%, respectively...
A Si-Glass based MEMS piezoresistive pressure sensor is designed for harsh environment applications, such as vibration, shock and environment conditions with humidity, alkalescence or acidity, electrostatic particles and so on. The sensor chips were fabricated using SOI wafer-glass anodic bonding technology, which enables a single boron-implanted piezoresistor to be on lower surface of silicon diaphragm...
The implementation of the dual-mass MEMS vibratory gyroscope in device-level vacuum packing was presented. The electrostatic actuation and capacitive sensing methods were adopted in electrical design of gyroscope. The self-resonance drive circuit with automatic gain control was employed in the drive closed-loop, and the open loop detect circuit was used. In order to reduce environment impact on the...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.