A MEMS IR sensor, with a cavity in a substrate underlapping an overlying layer and a temperature sensing component disposed in the overlying layer over the cavity, may be formed by forming an IR-absorbing sealing layer on the overlying layer so as to cover access holes to the cavity. The sealing layer is may include a photosensitive material, and the sealing layer may be patterned using a photolithographic process to form an IR-absorbing seal. Alternately, the sealing layer may be patterned using a mask and etch process to form the IR-absorbing seal.

A single silicon wafer micromachined thermal conduction sensor is described. The sensor consists of a heat transfer cavity with a flat bottom and an arbitrary plane shape, which is created in a silicon substrate. A heated resistor with a temperature dependence resistance is deposed on a thin film bridge, which is the top of the cavity. A heat sink is the flat bottom of the cavity and parallel to the bridge completely. The heat transfer from the heated resistor to the heat sink is modulated by the change of the thermal conductivity of the gas or gas mixture filled in the cavity. This change can be measured to determine the composition concentration of the gas mixture or the pressure of the air in a vacuum system.

A semiconductor device includes a first silicon layer with first and second regions of substantially different dopant concentration and a resonant MEMS member formed in the first region. A piezoelectric layer is disposed over the resonant MEMS member and conductive material is disposed over the piezoelectric layer and patterned to form first and second electrodes.

A microelectromechanical system (MEMS) resonator includes a substrate having a substantially planar surface and a resonant member having sidewalls disposed in a nominally perpendicular orientation with respect to the planar surface. Impurity dopant is introduced via the sidewalls of the resonant member such that a non-uniform dopant concentration profile is established along axis extending between the sidewalls parallel to the substrate surface and exhibits a relative minimum concentration in a middle region of the axis.

An accelerometer includes a housing, a proof mass assembly encased in the housing, and one or more heating elements configured to heat the proof mass assembly in response to an electrical current. The one or more heating elements include a positive temperature coefficient of resistance (PTC) material. The PTC material exhibits a relatively high increase in resistance above a threshold temperature. For example, a ratio of the resistance of the PTC material above the threshold temperature to the resistance of the PTC material at room temperature (PTC ratio) is greater than five.

An electromechanical systems structure including: providing a stack, including a structural layer extending in a plane, a sidewall layer including a first portion lying in a plane parallel to the structural layer plane and a second portion lying in a plane transverse to the structural layer plane, an etch-stop layer, positioned between the sidewall layer and the structural layer, including an etch-selectivity different from an etch-selectivity of the structural layer and an etch-selectivity of the sidewall layer, and a mold comprising a wall parallel to the sidewall layer's second portion; etching the sidewall layer's first portion to expose the etch-stop layer; removing the mold; etching the etch-stop layer such that the sidewall layer's second portion masks a portion of the etch-stop layer; removing the sidewall layer's second portion; and etching the structural layer such that the portion of the etch-stop layer masks a portion of the structural layer.

A MEMS device includes a substrate having a front surface and a rear surface, a recess formed in the front surface of the substrate, and a movable electrode and a fixed electrode connected to the substrate and disposed in such a manner as to face each other in the air above the recess. The movable electrode includes an embedded oxide layer embedded in a trench formed in the movable layer. A manufacturing method of a MEMS device includes forming a trench by etching the front surface of the substrate, and forming the embedded oxide layer in the trench by oxidating side surfaces and bottom surface of the trench.

A micro electro mechanical system (MEMS) includes a circuit substrate comprising electronic circuitry, a support substrate having a recess, a bonding layer disposed between the circuit substrate and the support substrate, through holes passing through the circuit substrate to the recess, a first conductive layer disposed on a front side of the circuit substrate, and a second conductive layer disposed on an inner wall of the recess. The first conductive layer extends into the through holes and the second conductive layer extends into the through holes and coupled to the first conductive layer.

A semiconductor device includes a first silicon layer with first and second regions of substantially different dopant concentration and a resonant MEMS member formed in the first region. A piezoelectric layer is disposed over the resonant MEMS member and conductive material is disposed over the piezoelectric layer and patterned to form first and second electrodes.

A method for manufacturing an optical microelectromechanical device, includes forming, in a first wafer of semiconductor material having a first surface and a second surface, a suspended mirror structure, a fixed structure surrounding the suspended mirror structure, elastic supporting elements extending between the fixed structure and the suspended mirror structure, and an actuation structure coupled to the suspended mirror structure. The method continues with forming, in a second wafer, a chamber delimited by a bottom wall having a through opening, and bonding the second wafer to the first surface of the first wafer and bonding a third wafer to the second surface of the first wafer so that the chamber overlies the actuation structure, and the through opening is aligned to the suspended mirror structure, thus forming a device composite wafer. The device composite wafer is diced to form an optical microelectromechanical device.