Texas Instruments Corporation

National Semiconductor Corporation

Terry Dyer

William David French

Roozbeh Parsa

Nathan Brockie

Ann Gabrys

Iouri N Mirgorodski

Andrew Derek Strachan

Peter J Hopper

Constantin Bulucea

Anuraag Mohan

Jim McGinty

An integrated microfabricated sensor includes a sensor cell having a cell body, a first window attached to the cell body, and a second window attached to the cell body. The cell body laterally surrounds a cavity, so that both windows are exposed to the cavity. The sensor cell contains a sensor fluid material in the cavity. The cavity has concave profiles at cell body walls, so that the cavity is wider in a central region, approximately midway between the first window and the second window, than at the first surface and at the second surface. The cell body walls of the cell body have acute interior angles at both windows. The cell body is formed using an etch process that removes material from the cell body concurrently at the first surface and the second surface, forming the acute interior angles at both the first surface and the second surface.

Concave cavity for integrated microfabricated sensor

An integrated microfabricated sensor includes a sensor cell having a cell body, a first window attached to a first surface, and a second window attached to a second surface, opposite to the first window. The cell body laterally surrounds a cavity, so that the first window and the second window are exposed to the cavity. The sensor cell contains a sensor fluid material in the cavity. The cell body has recesses on opposing exterior sides of the cell body; each recess extends from the first surface to the second surface. Exterior portions of the cell body wall in the recesses are recessed from singulation surfaces on the cell body exterior. The cell body is formed by etching the cavity and the recesses concurrently through a body substrate. After the windows are attached, the sensor cell is singulated from the body substrate through the recesses.

Microfabricated atomic clocks and magnetometers utilizing side recesses

A microfabricated sensor includes a sensor cell with a cell body and a window attached to the cell body. A sensor cavity containing sensor fluid material is located in cell body, open to the window. A signal path extends from a signal emitter outside the sensor cell, through the window and sensor cavity, and to a signal detector. The sensor cell may have an asymmetric thermal configuration, conducive to developing a temperature gradient in the sensor cell. One or more heaters are disposed on the sensor cell, possibly in an asymmetric configuration. Power is applied to the heaters, possibly asymmetrically, so as to develop a temperature gradient in the sensor cell with a low temperature region in the sensor cell, sufficient to condense the sensor fluid in the low temperature region, outside of the signal path.

Temperature gradient in microfabricated sensor cavity

A sensor cell has a chamber that defines an internal sensor volume for a sensor fluid in a vapor phase. A signal path extends into the internal sensor volume. The sensor cell includes a condensation reservoir for a condensed phase of the sensor fluid, in fluid communication with the internal sensor volume. The signal path is spatially separate from the condensation reservoir. During operation of the sensor cell, some of the sensor fluid may be converted to a vapor phase in the internal sensor volume. During such operation, sensor fluid in the condensed phase is disposed in the condensation reservoir, advantageously out of the signal path, leaving the signal path desirably free of the condensed phase sensor fluid. During periods of non-operation, a significant portion of the sensor fluid may condense from the vapor phase to the condensed phase in the condensation reservoir, advantageously out of the signal path.

Sensor fluid reservoirs for microfabricated sensor cells

A giant magneto-impedance (GMI) magnetometer is formed in a semiconductor wafer fabrication sequence, which significantly reduces the size and cost of the GMI magnetometer. The semiconductor wafer fabrication sequence forms a magnetic conductor, a non-magnetic conductor that is wrapped around the magnetic conductor as a coil, and non-magnetic conductors that touch the opposite ends of the magnetic conductor.

Semiconductor GMI magnetometer

Trenches are formed in a semiconductor substrate, where the trenches include an outer trench and multiple inner trenches within the outer trench. A metal-oxide semiconductor (MOS) device and a trench MOS Schottky barrier (TMBS) device are also formed in the semiconductor substrate using the trenches. The MOS device could include the outer trench, and the TMBS device could include the inner trenches. At least one of the inner trenches may contact the outer trench, and/or at least one of the inner trenches may be electrically isolated from the outer trench. The MOS device could represent a trench vertical double-diffused metal-oxide semiconductor (VDMOS) device, and the TMBS device may be monolithically integrated with the trench VDMOS device in the semiconductor substrate. A guard ring that covers portions of the inner trenches and that is open over other portions of the inner trenches could optionally be formed in the semiconductor substrate.

Method for integrating trench MOS Schottky barrier devices into integrated circuits and related semiconductor devices

An economical integration of trench VDMOS devices into a conventional BCD process is provided, with the optimization of key aspects of the device layout for low Rarea. Specifically, trench orientation, array geometry, the number of source cells between drain pickups and drain-source spacing are independently optimized. In one embodiment of the invention, the optimized device utilizes a rectangular cell array with an elongation ratio in the range of 5/3&#x2013;7/3, with a ratio of 5/3 being preferred, and a cell orientation at 45&#xb0; with respect to the wafer flat on a 100 wafer.

Layout optimization of integrated trench VDMOS arrays

The formation of vertical trench DMOS devices can be added to existing integrated BCD process flows in order to improve the efficiency of the BCD devices. The formation of this trench DMOS varies from existing approaches used with discrete trench DMOS devices, in that only two extra mask steps are added to the existing BCD process, instead of the 10 or so mask steps used in existing discrete trench DMOS processes. Further, the location of these additional heat cycles in the BCD process steps can be placed so as to have minimal impact on the other components created in the process. Utilizing an integrated trench device in a BCD process can offer at least a factor-of-two Rarea advantage over a planar counterpart.

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Terry Dyer