Low charging dielectric for capacitive MEMS devices and method of making same
AssigneeNorthrop Grumman Corporation
InventorsChristopher Kirby, Robert Horner, Harlan Cramer, Robert Howell, Robert Tranchini, Gregory DeSalvo, Gilbert Dix, Jeremiah Horner
Life of this patent
Estimating the term…
Abstract
An improved dielectric suitable for use in electronic and micro-electromechanical (MEMS) components. The dielectric includes silicon nitride having a percentage of Si:H bonds greater than a percentage of N:H bonds, in order to reduce the level of charge trapping of the silicon nitride.
Claims39
An improved dielectric comprising:
- silicon nitride having a percentage of Si—H bonds greater than a percentage of N—H bonds.
A micro-electro-mechanical system (MEMS) device comprising:
- an electrode;
- and
- a dielectric film deposited on the electrode, said dielectric film comprising silicon nitride having an amount of Si—H bonds that exceeds an amount of N—H bonds.
A method of fabricating an improved dielectric, comprising:
- depositing silicon nitride by plasma enhanced chemical vapor deposition, wherein N—H bonds in said silicon nitride are shift to Si—H bonds in order to reduce charge trapping capability of said dielectric.
A method of optimizing fabrication of a micro-electromechanical (MEMS) device, comprising the steps of:
- (a) depositing a dielectric film on a test structure under similar conditions as said dielectric film would be deposited on an electrode of said MEMS device;
- (b) determining an amount of trapped charge within said deposited dielectric film;
- (c) adjusting at least one process parameter of said depositing step (a) in order to reduce the amount of trapped charge within said dielectric film;
- (d) repeating steps (a)-(c) until the amount of trapped charge within said dielectric film has been minimized;
- and (e) thereafter using said adjusted process parameters to fabricate said MEMS device.
A method of determining an amount of trapped charge in a dielectric film of a micro-electromechanical (MEMS) device fabricated in accordance with a plurality of specific process conditions, comprising steps of:
- depositing a dielectric film on a silicon wafer, said dielectric film being deposited under the same conditions as said dielectric film of said MEMS device;
- depositing a metal layer on top of said dielectric film;
- biasing the structure created by said metal layer and said dielectric film with a bias voltage;
- measuring a flatband voltage and a flatband capacitance of said structure;
- and
- calculating an amount of trapped charge based on said flatband voltage and flatband capacitance measured.
A method of fabricating a capacitive MEMS switch having a dielectric film, comprising:
- a step for fabricating a M-I-S structure on a dielectric film;
- a step for determining an amount of trapped charge in said dielectric film of said MIS structure;
- a step for determining optimum process parameters associated with depositing said dielectric film to minimize the amount of trapped charge in said dielectric film as determined by said trapped charge amount determining step;
- and
- a step for fabricating said MEMS switch utilizing said optimum process parameters to deposit said dielectric film.
Dependencies are inferred from the claim text.