Jeffrey W Lang

US Patent:

49975218, Mar 5, 1991

Filed:

Apr 25, 1989

Appl. No.:

7/342952

Inventors:

Roger T. Howe - Lafayette CA
Jeffrey H. Lang - Waltham MA
Martin F. Schlecht - Lexington MA
Martin A. Schmidt - Newton Highlands MA
Stephen D. Senturia - Boston MA

Assignee:

Massachusetts Institute of Technology - Cambridge MA

International Classification:

H01L 21306

US Classification:

156651

Abstract:

An electrostatically driven microactuator is micromachined in a monolithic process. Sacrificial layers are placed between a moving element and stator structural layers. Removal of the sacrificial layers leaves a free standing moving element and micron wide air gaps within a stator. An electric field of about 100 Mv/m and higher is supported across the micron wide gap without breakdown and enables high energy torque densities to be produced between the stator and the moving element. One electrostatic drive scheme involves a series of stator electrodes attached to the stator and a series of electrodes attached to the moving element charged in sequence to attract each other in a direction of movement and to oppose each other in a direction normal to movement. A bearing is aligned with the moving element within the stator during the layering of a sacrificial layer over an edge of the moving element structural layer. The bearing and stator laterally stabilize the moving element.

US Patent:

50430432, Aug 27, 1991

Filed:

Jun 22, 1990

Appl. No.:

7/542435

Inventors:

Roger T. Howe - Lafayette CA
Jeffrey H. Lang - Waltham MA
Martin F. Schlecht - Lexington MA
Martin A. Schmidt - Newton Highlands MA
Stephen D. Senturia - Boston MA
Mehran Mehregany - Shaker Heights OH
Lee S. Tavrow - Somerville MA

Assignee:

Massachusetts Institute of Technology - Cambridge MA

International Classification:

H01L 21306
B44C 122
C03C 1500
C03C 2506

US Classification:

156645

Abstract:

An electrostatic micromotor employs a side drive design. The stator operates in a plane above a substract and a moveable member lies and moves in the plane of the stator. An electrostatic field of operational strength is generated and sustained without breakdown in the plane between the stator and edges of the moveable member. Three fabrication processes enable formation of a moveable member in the plane of operation of the stator and spaced apart from the stator by a micron amount. One fabrication process deposits and patterns a structural layer to form the stator and moveable member over a sacrificial layer. A second fabrication process etches channels in a first structural layer to outline a stator, moveable member, and if desired, a bearing. A substrate is connected to the side of the structural layer through which the channels are etched and the opposite side is ground down to the ends of the channels to form salient stator, rotor and, if desired, bearing structures. The third fabrication process grows a sacrificial layer by local oxidation in an etched cavity of the substrate.