Abstract:
Layers of boron-doped silicon (36) having reduced out-of-plane curvature are disclosed. The layers have substantially equal concentrations of boron near th etop (38) and bottom (40) surfaces. Since the opposing concentrations are substantially equal, the compressive stresses on the layers (36) are substantially balanced, thereby resulting in layers (36) with reduced out-of-plane curvature.
Abstract:
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.
Abstract:
The invention relates to a micromechanical device comprising a semiconductor element capable of deflecting or resonating and comprising at least two regions having different material properties and drive or sense means functionally coupled to said semiconductor element. According to the invention, at least one of said regions comprises one or more n-type doping agents, and the relative volumes, doping concentrations, doping agents and/or crystal orientations of the regions being configured so that the temperature sensitivities of the generalized stiffness are opposite in sign at least at one temperature for the regions, and the overall temperature drift of the generalized stiffness of the semiconductor element is 50 ppm or less on a temperature range of 100° C. The device can be a resonator. Also a method of designing the device is disclosed.