Device with a stress decoupling structure
A MEMS device comprises a suspended membrane structure having an inner membrane section and an outer membrane section. The outer membrane section surrounds the inner membrane section. The membrane structure comprises an elastically deformable spring structure in the outer membrane section, such that the spring structure is arranged to convert a thermal-induced compressive stress in the suspended membrane structure into a spring displacement.
1 . A micro-electro-mechanical system (MEMS) device comprising:
a suspended membrane structure having an inner membrane section and an outer membrane section, wherein the outer membrane section at least partially surrounds the inner membrane section; and
a spring structure that is elastically deformable in the outer membrane section, wherein the spring structure is arranged to respond to a thermal-induced compressive stress in the suspended membrane structure with a spring displacement of the spring structure.
2 . The MEMS device of claim 1 , wherein a lateral surface area of the spring structure is less than 40% of a lateral surface area of the membrane structure.
3 . The MEMS device of claim 1 , wherein the spring structure has a mechanical rigidity about two-times less than a mechanical rigidity of the remaining membrane structure.
4 . The MEMS device of claim 2 , wherein the spring structure forms a locally confined displacement region in the outer membrane section of the membrane structure.
5 . The MEMS device of claim 1 , wherein the spring structure comprises a trench structure.
6 . The MEMS device of claim 5 , wherein the trench structure comprises overlapped trenches or a meander-shaped trench.
7 . The MEMS device of claim 1 , wherein the spring structure comprises at least one spring element formed by two neighboring and laterally spaced trenches or slits.
8 . The MEMS device of claim 7 , wherein the spring element is formed as a strip or leaf spring in the outer membrane section.
9 . The MEMS device of claim 7 , wherein the spring element extends in the outer membrane section parallel to a circumferential line of the membrane structure or extends along a contour line of membrane deflection.
10 . The MEMS device of claim 7 , wherein the spring structure comprises a plurality of spring elements respectively formed by two neighboring and laterally spaced trenches or slits.
11 . The MEMS device of claim 10 , wherein the spring elements are formed as parallel strips or leaf springs, and wherein the spring elements partially surround the inner membrane section.
12 . The MEMS device of claim 10 , wherein respective widths of the spring elements are chosen to provide at least one of: equal stiffness, equal electrical resistance, and equal distance of the spring elements.
13 . The MEMS device of claim 10 , wherein the spring elements are distributed in a pattern in the outer membrane section and extend parallel to a circumferential line of the membrane structure or along a contour line of membrane deflection.
14 . The MEMS device of claim 1 , wherein the suspended membrane structure is edge clamped to a support structure and spans across a cavity in the support structure.
15 . The MEMS device of claim 1 , wherein the suspended membrane structure comprises an integrated resistor which is arranged to be heated by application of a voltage.
16 . The MEMS device of claim 1 , wherein the spring structure comprises a slit structure.
17 . The MEMS device of claim 1 , wherein the spring structure comprises a lined-up hole structure.
18 . A MEMS device comprising:
a membrane structure having an inner membrane section and an outer membrane section at least partially surrounding the inner membrane section; and
a spring structure formed in the outer membrane section by at least two parallel trenches penetrating the outer membrane section, wherein the spring structure is configured to respond to a thermal stress in the membrane structure with a mechanical deformation between the two parallel trenches.
19 . The MEMS device of claim 18 , wherein the membrane structure is edge clamped to a support structure and spans across a cavity in the support structure.
20 . The MEMS device of claim 18 , wherein the membrane structure comprises an integrated resistor which is arranged to be heated by application of a voltage.