Thomas A Mcgill

US Patent:

6579068, Jun 17, 2003

Filed:

Aug 7, 2001

Appl. No.:

09/923483

Inventors:

Paul M. Bridger - Pasadena CA
Robert P. Strittmatter - Pasadena CA
Robert A. Beach - Pasadena CA
Thomas C. McGill - Pasadena CA

Assignee:

California Institute of Technology - Pasadena CA

International Classification:

F04B 1924

US Classification:

417 53, 4174132, 4174131, 417322

Abstract:

A suspended p-GaN membrane is formed using photochemical etching which membrane can then be used in a variety of MEMS devices. In the illustrated embodiment a pump is comprised of the p-GaN membrane suspended between two opposing, parallel n-GaN support pillars, which are anchored to a rigid substrate below the pillars. The p-GaN membrane bows upward between the pillars in order to relieve stress built up during the epitaxial growth of membrane. This bowing substantially increases the volume of the enclosed micro-channel defined between membrane and substrate below. The ends of membrane are finished off by a gradual transition to the flat underlying n-GaN layer in which fluidic channels may also be defined to provide inlet and outlet channels to microchannel. A traveling wave or sequential voltage applied to the electrodes causes the membrane to deform and provide a peristaltic pumping action in the microchannel.

US Patent:

6647796, Nov 18, 2003

Filed:

Aug 7, 2001

Appl. No.:

09/923628

Inventors:

Robert A. Beach - Altadena CA
Robert P. Strittmatter - Pasadena CA
Thomas C. McGill - Pasadena CA

Assignee:

California Institue of Technology - Pasadena CA

International Classification:

G01L 900

US Classification:

73754, 73720, 73726, 257254

Abstract:

An integrated microsensor includes a bowed micromachined membrane coupled to a substrate to define a microcavity therebetween. An integrated strain sensor is coupled to the micromachined membrane to generate a signal responsive to (deformation of the membrane and hence responsive to the pressure of the fluid in the microcavity. A frame is coupled to the peripheral edge of the membrane to assist in enlarging the microcavity. The membrane is composed of a nitride of B, Al, Ga, In, Tl or combinations thereof, or more particularly of p-type GaN where the frame is comprised of n-type GaN. The membrane and frame are fabricated using a photoelectrochemical etching technique. The fabrication of the integrated strain sensor creates stresses across the membrane. The strain sensor comprises an integrated circuit strain-FET. The strain-FET comprises an AlGaN/GaN heterostructure having an AlGaN/GaN interface where deformation of the membrane is coupled as strain to the AlGaN/GaN piezoelectric interface.

US Patent:

7189358, Mar 13, 2007

Filed:

Aug 7, 2001

Appl. No.:

09/923582

Inventors:

Robert A. Beach - Altadena CA, US
Robert P. Strittmatter - Pasadena CA, US
Thomas C. McGill - Pasadena CA, US

Assignee:

California Institute of Technology - Pasadena CA

International Classification:

G01N 15/06
G01N 33/00
G01N 33/48
H01L 21/302
E03B 1/00

US Classification:

422 681, 422 50, 422 61, 422 63, 422100, 422 81, 422 8205, 422103, 422104, 436 43, 436174, 73 101, 73 102, 73 116, 73 169, 73 171, 438689, 137 1, 137255, 417 1

Abstract:

An integrated micropump or a plurality of integrated micropumps are communicated to a plurality of analysis chambers. A plurality of integrated analysis chambers include integrated analysis devices to test a fluid for an analyte. The micropumps continuously or periodically pump the fluid into the analysis chambers and flush the analysis chambers after analysis of the analyte. In one embodiment, the analysis device comprises an integrated LED and an integrated optical detector. The LED and detector are tuned to an optical absorption line of the analyte. The micropumps are composed of nitrides of B, Al, Ga, In, Tl or combinations thereof and fabricated using photoelectrochemical techniques. The analysis chambers, and micropumps including the analysis devices are simultaneously fabricated during which fabrication of the micropumps and the analysis devices are masked from the photoelectrochemical techniques.

US Patent:

6078055, Jun 20, 2000

Filed:

Mar 18, 1998

Appl. No.:

9/044082

Inventors:

Paul M. Bridger - Pasadena CA
Thomas C. McGill - Pasadena CA

Assignee:

California Institute of Technology - Pasadena CA

International Classification:

H01J 37304

US Classification:

2504922

Abstract:

A proximity lithography device using a modified electric field. In the preferred embodiment, the modified electric field is formed by illuminating a tip of a scanning probe in close proximity of the resist surface with a laser. In an alternate embodiment, the modified electric field is formed by positioning a tip of a scanning probe within close proximity of the resist surface, where illumination from a laser is in total internal reflection within the resist. The proximity of the tip to the resist surface creates a tunneling effect and forms the modified electric field. The modified electric field alters the resist for lithographic patterning.

US Patent:

60157380, Jan 18, 2000

Filed:

Nov 17, 1997

Appl. No.:

8/972118

Inventors:

Harold J. Levy - Seal Beach CA
Thomas C. McGill - Pasadena CA

Assignee:

California Institute of Technology - Pasadena CA

International Classification:

H01L 218246

US Classification:

438275

Abstract:

A transistorless memory cell for storing information as one of two possible bistable current states comprises (i) at least one first transistorless device exhibiting N-type negative differential resistance, including a high-impedance region, a low-impedance region and a negative-resistance region and having a polarity and (ii) at least one second transistorless device exhibiting an exponential or linear current-voltage characteristic and coupled to the first transistorless device. The read/write operation of the transistorless memory cell is performed in a current mode. A method for fabricating a self-aligned, three-dimensional structure of memory cells comprises the steps of (i) forming a first conducting layer, (ii) forming a first semiconductor layer above the first conducting layer, (iii) forming a second semiconductor layer above the first semiconductor layer, (iv) patterning the second semiconductor layer, (v) etching the second semiconductor layer, the first semiconductor layer and the first conducting layer, (vi) forming a second conducting layer above the second semiconductor layer, (vii) patterning and etching the second conducting layer, and (viii) etching the second semiconductor layer using the second conducting layer as a mask to form multiple semiconducting devices of a second kind, and etching the first semiconductor layer using the second conducting layer as a mask to form multiple semiconducting devices of a first kind.

US Patent:

62884042, Sep 11, 2001

Filed:

May 26, 2000

Appl. No.:

9/579450

Inventors:

Paul M. Bridger - Pasadena CA
Thomas C. McGill - Pasadena CA

Assignee:

California Institute of Technology - Pasadena CA

International Classification:

H01J 37304

US Classification:

2504922

Abstract:

A proximity lithography device using a modified electric field. In the preferred embodiment, the modified electric field is formed by illuminating a tip of a scanning probe in close proximity of the resist surface with a laser. In an alternate embodiment, the modified electric field is formed by positioning a tip of a scanning probe within close proximity of the resist surface, where illumination from a laser is in total internal reflection within the resist. The proximity of the tip to the resist surface creates a tunneling effect and forms the modified electric field. The modified electric field alters the resist for lithographic patterning.

US Patent:

51132311, May 12, 1992

Filed:

Sep 7, 1989

Appl. No.:

7/404148

Inventors:

Jan R. Soderstrom - Pasadena CA
Thomas C. McGill - Pasadena CA

Assignee:

California Institute of Technology - Pasadena CA

International Classification:

H01L 29205

US Classification:

357 16

Abstract:

A novel combination of semiconductor heterojunctions provide a quantum-effect device with resonant or enhanced transmission of electrons (or holes) due to tunneling into a quantum well state in the valence (or conduction) band. A particular heterostructure comprising sequentially grown layers of indium arsenide, aluminum antimonide, gallium antimonide, aluminum antimonide and indium arsenide, permits electrons tunneling from the indium arsenide conduction band through the aluminum antimonide barrier into a sub-band level in the valence band quantum well of the gallium antimonide. This particular embodiment produced a current-voltage characteristic with negative differential resistance and a peak-to-valley current ratio of about 20 at room temperature and 88 at liquid nitrogen temperature. The present invention can be used either as a two-contact device such as a diode or a three-contact device such as a transistor.

US Patent:

57727589, Jun 30, 1998

Filed:

Feb 15, 1996

Appl. No.:

8/602144

Inventors:

Douglas A. Collins - Pasadena CA
Thomas C. McGill - Pasadena CA
George O. Papa - Pasadena CA

Assignee:

California Institute of Technology - Pasadena CA

International Classification:

C30B 2516

US Classification:

117 85

Abstract:

Methods and apparatus are provided for monitoring deposition and pre-deposition characteristics such as the growth rates, oxide desorption, surface reconstruction, anion surface exchange reaction and smoothness of the surface of rotating substrates in near real-time during molecular beam epitaxy by processing the data in the time domain and for controlling a deposition apparatus in near real-time. An apparatus for extracting the characteristics and controlling the deposition apparatus in near real-time includes the following: (a) the deposition apparatus having a rotating substrate, (b) an energy pattern generator for subjecting the substrate to a beam of energy and for producing energy patterns, (c) an imaging unit for obtaining video images of the energy patterns, video images each having pixels, (d) a data processing unit for monitoring a selected set of the pixels on each of the video images, generating time-domain data for each video image and generating deposition parameters in near real-time, and (e) a deposition control unit for controlling the deposition apparatus in response to receiving the deposition parameters in near real-time. The method of extracting the characteristics and controlling the deposition apparatus in near real-time includes the following steps: obtaining video images of energy patterns coming from the substrate, monitoring a selected set of the pixels on each video image to generate time-domain data, filtering the time-domain data in near real-time, and controlling the deposition apparatus in near real-time.