Polycrystalline silicon-germanium films for micro-electromechanical systems application

• US 6,448,622 B1
• Filed: 07/17/2000
• Issued: 09/10/2002
• Est. Priority Date: 01/15/1999
• Status: Expired due to Term

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Howe, Roger T., Franke, Andrea, King, Tsu-Jae
• Primary Examiner(s): Flynn, Nathan
• Assistant Examiner(s): Wilson, Scott R
• Application Number:
  US09/617,300
• Time in Patent Office: 785 Days
• Field of Search: 438/50, 438/53, 257/414, 257/415, 257/416
• US Class Current: 257/415
• CPC Class Codes: B81B 2203/0118 Cantilevers
• CPC Class Codes: B81C 1/00246 Monolithic integration, i.e. micromechanical structure and electronic processing unit are integrated on the same substrate
• CPC Class Codes: B81C 2201/0109 Sacrificial layers not provided for in B81C2201/0107 - B81C2201/0108
• CPC Class Codes: B81C 2203/0735 Post-CMOS, i.e. forming the micromechanical structure after the CMOS circuit
• CPC Class Codes: Y10S 438/933 Germanium or silicon or Ge-Si on III-V

Abstract

This invention relates to micro-electromechanical systems using silicon-germanium films. Such a system includes one or more layers of Si_1−xGe_x, deposited on a substrate, where 0<x≦1. One or more transistors can be formed on the substrate.

Claims

1. A micro-electromechanical system, comprising:

a substrate;

one or more structural layers of Si<sub>1−

x</sub>Ge_x, deposited on the substrate, where 0<

x≦

1; and

one or more transistors formed on the substrate.

2. The micro-electromechanical system of claim 1, wherein the substrate is a silicon substrate.

3. The micro-electromechanical system of claim 1, wherein the substrate is a glass substrate.

4. The micro-electromechanical system of claim 1, further comprising at least portions of one or more sacrificial layers of silicon oxide formed under respective structural layers.

5. The micro-electromechanical system of claim 1, wherein the one or more transistors are MOS transistors.

6. The micro-electromechanical system of claim 1, wherein the one or more transistors are bipolar transistors.

7. The micro-electromechanical system of claim 1, incorporated into an optical device.

8. The micro-electromechanical system of claim 1, wherein the one or more structural layers form a resonator.

9. A micro-electromechanical system, comprising:

a substrate;

one or more structural layers of Si<sub>1−

x</sub>Ge_x, formed on the substrate, where 0<

x≦

1;

at least portions of one or more sacrificial layers of silicon-germanium formed under the respective structural layers, where the germanium content of the one or more sacrificial layers is greater than the germanium content of the respective structural layers; and

one or more transistors formed on the substrate.

10. A micro-electromechanical system, comprising:

a substrate;

one or more structural layers of Si<sub>1−

x</sub>Ge_x, formed on the substrate, where 0<

x≦

1 and wherein the germanium concentration of at least one structural layer varies through its depth; and

one or more transistors formed on the substrate.

11. The micro-electromechanical system of claim 10, wherein the at least one structural layer has a desired three-dimensional shape.

12. A micro-electromechanical system, comprising:

a substrate;

one or more transistors formed on the substrate; and

one or more structural layers of Si<sub>1−

x</sub>Ge_x, deposited onto an upper level of a metal interconnect of the one or more transistors, where 0<

x≦

1.

13. The micro-electromechanical system of claim 12, wherein the one or more structural layers form a ground plane which is electrically connected to the upper level of the metal interconnect.