Abstract: A semiconductor device (8) has a movable gate (20) over a semiconductor substrate (14) having a top surface (30). Source and drain regions (16-19) are in the substrate, and a channel region (24,25) is between the source and drain regions. The gate is suspended above the source and drain regions such that the gate is movable in a plane substantially parallel to the top surface of the substrate. In one embodiment the device is an accelerometer having the gate connected to a beam (10) with an aspect ratio between 2:1 and 10:1. Also, the gate can have first and second levels (22,23) corresponding to first and second threshold voltages of the channel region.

Abstract: A semiconductor device (15) having a sensor (11) and a transistor (10) formed on a monolithic semiconductor substrate (16). The sensor (11) has a source region (41), a drain region (42), and a microstructure (12) which is formed from a conductive layer (28). The microstructure (12) modulates a channel region between the source and drain regions (41,42). The transistor has a gate structure, a portion of which is formed from the same conductive layer (28) used to form the microstructure (12). Anneal steps are performed on the conductive layer (28) to remove stress prior to the formation of source and drain regions (34,36) of the transistor (10). A self-test structure (14) is formed adjacent to the microstructure (12) which is used to calibrate and verify the operation of the sensor (11).

Abstract: Converting a Coriolis force into an electrical signal, an electro-mechanical transducer (10) is a field effect transistor (18) having angular velocity sensing capabilities. A gate electrode (16) is suspended over a channel region (60) of a substrate (31), is biased at a desired potential, and is oscillated along an axis (40). The gate electrode (16) and the substrate (31) are rotated about a different axis (41) at an angular velocity (44). The resulting Coriolis force displaces the suspended gate electrode (16) along yet another axis (42) which modulates a current (53) in the channel region (60) of the substrate (31). The amplitude of the current (53) describes the magnitude of the angular velocity (44).

Abstract: A reactive ion etching process is used for the fabrication of submicron, single crystal silicon, movable mechanical structures and capacitive actuators. The reactive ion etching process gives excellent control of lateral dimensions while maintaining a large vertical depth in the formation of high aspect-ratio freely suspended single crystal silicon structures. The silicon etch process is independent of crystal orientation and produces controllable vertical profiles.

Abstract: A reactive ion etching process is used for the fabrication of submicron, single crystal silicon, movable mechanical structures and capacitive actuators. The reactive ion etching process gives excellent control of lateral dimensions while maintaining a large vertical depth in the formation of high aspect-ratio freely suspended single crystal silicon structures. The silicon etch process is independent of crystal orientation and produces controllable vertical profiles.

Abstract: A selective chemical vapor deposition (CVD) tungsten process is used to fabricate three-dimensional tungsten cantilever beams on a substrate. Two beams form micromechanical tweezers that move in three dimensions by the application of potential differences between the beams, and between the beams and the silicon substrate. A high deposition rate selective tungsten CVD process is used to fabricate beams of greater than 3 micrometers thickness in patterned, CVD silicon dioxide trenches ion-implanted with silicon. Tweezers 200 micrometers in length with a cross section of 2.7 by 2.5 micrometers will close upon application of a voltage of less than 150 volts.

Abstract: A selective chemical vapor deposition (CVD) tungsten process is used to fabricate three-dimensional tungsten cantilever beams on a substrate. Two beams form micromechanical tweezers that move in three dimensions by the application of potential differences between the beams, and between the beams and the silicon substrate. A high deposition rate selective tungsten CVD process is used to fabricate beams of greater than 3 micrometers thickness in patterned, CVD silicon dioxide trenches ion-implanted with silicon. Tweezers 200 micrometers in length with a cross section of 2.7 by 2.5 micrometers will close upon application of a voltage of less than 150 volts.