Temperature compensation in a semiconductor micromechanical resonator via charge carrier depletion

Patent metadata

Field	Value
Publication number	US-9319020-B2
Application number	US-201113276931-A
Country	US
Kind code	B2
Filing date	Oct 19, 2011
Priority date	Oct 19, 2010
Publication date	Apr 19, 2016
Grant date	Apr 19, 2016

Abstract

A semiconductor resonator has a substrate with a thickness extending between a first end and a second end and a pn-junction along the thickness of the substrate forming a free charge carrier depletion region. In another embodiment, a semiconductor resonator has a substrate with a crystal lattice doped at degenerate levels such that the flow of free charge carriers can be minimized. A method of compensating a temperature coefficient of a semiconductor resonator by creating a pn-junction based free charge carrier depletion region within a thickness of a substrate of the resonator is also disclosed.

First claim

What is claimed is:

1. A semiconductor resonator, comprising:
a resonator body having a thickness extending between a first end and a second end; and
a mechanism for reducing a temperature coefficient of frequency of the resonator comprising at least one pn-junction along the thickness of the resonator body forming a free charge carrier depletion region configured for minimizing a flow of free charge carriers therethrough.

2. The resonator of claim 1 , wherein the resonator body comprises doped silicon.

3. The resonator of claim 1 , wherein the resonator body is an n-type substrate.

4. The resonator of claim 1 , wherein the resonator body is an n-type substrate doped with a p-type dopant.

5. The resonator of claim 1 , wherein the resonator body is a phosphorous doped n-type substrate.

6. The resonator of claim 1 , wherein the resonator body is doped with boron.

7. The resonator of claim 1 , wherein the resonator body is a p-type substrate doped with an n-type dopant.

8. The resonator of claim 1 , wherein the resonator body is doped with solid boron.

9. The resonator of claim 1 , wherein the resonator body is doped using liquid boron.

10. The resonator of claim 1 , wherein the resonator body comprises at least one of an n-type or p-type material lightly doped with the other of the n-type or p-type material.

11. The resonator of claim 1 , wherein the resonator body is further defined by a pair of concave surfaces extending between the first and second ends thereof such that the resonator body is wider proximate the ends thereof and narrower proximate a center portion thereof.

12. The resonator of claim 11 , wherein the center portion is approximately two thirds as long as the end regions of the resonator.

13. A semiconductor resonator, comprising:
a resonator body having a thickness extending between a first end and a second end;
a plurality of at least three pn-junction layers along the thickness of the resonator body forming a plurality of at least three free charge carrier depletion regions.

14. The resonator of claim 13 , wherein the resonator body is further defined by a pair of concave surfaces extending between a first end and a second end thereof such that the resonator body is wider proximate the ends thereof and narrower proximate a center portion thereof.

15. A method of compensating a temperature coefficient of a semiconductor resonator, comprising:
A) providing a resonator body having a thickness extending between first and second ends thereof;
B) creating a pry-junction based free charge carrier depletion region along the thickness of the resonator body of the resonator.

16. The method of claim 15 , wherein B) comprises B1) lightly doping the resonator body having at least one of an n-type or p-type material with the other of the n-type or p-type material.

17. The method of claim 16 , wherein B1) comprises:
B1a) doping a phosphorous doped n-type resonator body with a solid p-type dopant; and
B1b) annealing the doped resonator body.

18. The method of claim 16 , wherein B1) comprises:
B1a) doping a phosphorous doped n-type resonator body with a liquid p-type dopant; and
B1b) annealing the doped resonator body.

Assignees

• Ayazi Farrokh
• Samarao Ashwin
• Georgia Tech Res Inst

Inventors

• Ayazi Farrokh
• Samarao Ashwin

Classifications

• H03H9/02448

  of temperature influence · CPC title

• H03H2009/2415

  with concave shape [CBAR] · CPC title

• B81B3/0081

  Thermal properties · CPC title

• H03H9/2463

  Clamped-clamped beam resonators · CPC title

• H03H2009/02496

  Horizontal, i.e. parallel to the substrate plane · CPC title