Carnegie Mellon University

Spts Technologies Limited

John J Neumann, Jr

Kaigham Jacob Gabriel

Kyle S Lebouitz

Wayne A Loeb

Brett Mathew Diamond

David L Springer

Todd M Przybycien

Steinar Hauan

Michael Bartkovsky

According to the invention there is provided a method of dry gas phase chemically etching a structure comprising the steps of: positioning the structure in an etch chamber, the structure comprising a first material and a second material, wherein the first material is selected from silicon, molybdenum, germanium, SiGe and tungsten, the second material is silicon dioxide or silicon nitride, and at least one surface of the first material is exposed so as to be contactable by a gas phase chemical etchant; etching the first material with a noble gas fluoride or halogen fluoride gas phase chemical etchant; and exposing the etch chamber to water vapour so that the step of etching the first material is performed in the presence of water vapour.

Method and apparatus for dry gas phase chemically etching a structure

In a method of vapor etching, a sample that includes a first layer atop of and in contact with a second layer which is atop of and in contact with a third layer, wherein at least the first and second layers are comprised of different materials. The sample is etched by a vapor etchant under first process conditions that cause at least a part of the first layer to be fully removed while leaving the third layer and the second layer underlying the removed part of the first layer substantially unetched. The sample is then etched by the same or a different vapor etchant under second process conditions that cause at least the part of the second layer exposed by the removal of the at least part of the first layer to be fully removed while leaving the third layer underlying the removed part of the second layer substantially unetched.

Selective etching of semiconductor substrate(s) that preserves underlying dielectric layers

A micro-electro-mechanical system (MEMS) device is described having a membrane which can be induced to resonate and the frequency of its resonance can be monitored. Chemical moieties can be attached to the membrane, and these moieties can be selected such that they have an affinity for molecules of interest, especially biological molecules of interest. When molecules of interest bind to the moieties they increase the mass of the membrane and thereby change the frequency of the membrane's resonance. By monitoring the resonance one can obtain an indication of the presence of the molecules of interest and in some circumstances an indication of the approximate concentration of these molecules. In addition, several types of moieties having affinities for several different molecules of interest can be placed on the membrane in such a way that the sensor can detect the presence of several different types of molecules of interest and distinguish which ones may be present and which ones may be absent.

MEMS membrane based sensor

An acoustic transducer comprising a substrate; and a diaphragm formed by depositing a micromachined membrane onto the substrate. The diaphragm is formed as a single silicon chip using a CMOS MEMS (microelectromechanical systems) semiconductor fabrication process. The curling of the diaphragm during fabrication is reduced by depositing the micromachined membrane for the diaphragm in a serpentine-spring configuration with alternating longer and shorter arms. As a microspeaker, the acoustic transducer of the present invention converts a digital audio input signal directly into a sound wave, resulting in a very high quality sound reproduction at a lower cost of production in comparison to conventional acoustic transducers. The micromachined diaphragm may also be used in microphone applications.

MEMS digital-to-acoustic transducer with error cancellation

Each of a plurality of speaklets (MEMS membranes) produces a stream of clicks (discrete pulses of acoustic energy) that are summed to generate the desired soundwave. The speaklets are selected to be energized based on the value of a digital signal. The greater the significance of the bit of the digital signal, the more speaklets that are energized in response to that bit. Thus, a time-varying sound level is generated by time-varying the number of speaklets emitting clicks. Louder sound is generated by increasing the number of speaklets emitting clicks. The present invention represents a substantial advance over the prior art in that sound is generated directly from a digital signal without the need to convert the digital signal first to an analog signal for driving a diaphragm.

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Pittsburgh, PA, United States of America

John J Neumann, Jr