Carl E Colvard

US Patent:

58726292, Feb 16, 1999

Filed:

Jun 23, 1997

Appl. No.:

8/880942

Inventors:

Carl Colvard - Palo Alto CA

Assignee:

Charles Evans & Associates - Redwood City CA

International Classification:

G01B 902

US Classification:

356349

Abstract:

A device for measuring changes in the relative height or depth of microscopic surface features of a sample that allows crater depth measurements to be made while depth profile analyses are proceeding is provided. The depth monitor comprises a dual beam optical interferometer, that is preferably adapted for use with analytical instruments, such as SIMS, XPS, ESCA, and AES instruments. The monitor provides substantially accurate depth measurements and a continuous readout for monitoring the sputter rate of an ion beam etch in real time, for correcting for any variations in the sputter rate as craters are formed in the sample. The invention also allows integration of real time depth measurements into data collecting software to eliminate the assumption that the material comprising the sample has the same sputter rate as a reference material. The in situ depth measurements provided by the invention are more accurate than prior art crater depth analysis and reduce processing times. The dual beam design of the monitor assures that fluctuations in the total path length of the beams, do not affect depth measurement of craters in the sample.

US Patent:

51073161, Apr 21, 1992

Filed:

Dec 28, 1989

Appl. No.:

7/458031

Inventors:

Kevin W. Jelley - Allentown NJ
Carl Colvard - Sunnyvale CA

Assignee:

Siemens Corporate Research, Inc. - Princeton NJ

International Classification:

H01L 310352
H01L 2966

US Classification:

357 25

Abstract:

Apparatus for detecting the presence of a gas in an ambient atmosphere comprises a multiple quantum well structure; a thin layer of a transition metal formed on the multiple quantum well structure; and an arrangement for monitoring the transmission of electromagnetic radiation sent through the multiple quantum well structure and reflected back therethrough by the thin layer.