At&t Bell Laboratories

Bell Telephone Laboratories

American Telephone & Telegraph Co., At&t Bell Laboratories

Avid Kamgar

Ashok K Sinha

Ronald J Schutz

Louis C Parrillo

Dawon Kahng

Simon M Sze

Chuan C Chang

Ernest Labate

Gregory M Gutt

Joseph R Ligenza

Robert V Knoell

Disclosed is a method for manufacturing an integrated circuit which includes the step of evaluating the reliability of metal films in the circuit using a noise measurement technique. In one embodiment, a film portion to be tested is incorporated in a Wheatstone bridge. A relatively large direct current is passed through the film to stimulate 1/f.sup.2 noise. A relatively small alternating current is concurrently passed through the film. The bridge imbalance signal at the ac frequency is amplified and demodulated by a phase-locked amplifier, and is then frequency analyzed. The film is evaluated by comparing the resulting noise power spectrum with predetermined standards.

Method for reliability testing integrated circuit metal films

Semiconductor crystal films on a dielectric substrate are advantageously made by a zone melting method. Single-crystal structure is initiated at a seed surface, and made to extend across a dielectric surface by melting and resolidifying. Melting is effected upon irradiation with optical radiation which is focused onto an elongated zone; the zone is moved so as to locally melt successive portions of a layer of precursor material which may be amorphous or polycrystalline. The use of incoherent radiation is convenient, and focusing is typically by using a reflector. The process is conveniently effected under a controlled atmosphere and the layer being crystallized may be encapsulated so that no free semiconductor surface is exposed to an atmosphere.

Method for making semiconductor crystal films

A semiconductor integrated circuit includes a nitrided silicon dioxide layer typically 50 to 400 Angstroms thick located on a semiconductor medium. The nitrided layer is an original silicon dioxide layer that has been nitrided at its top surface, as by rapid (flash) heating in ammonia to about 1250 degrees C., in such a way that the resulting nitrided silicon dioxide layer is essentially a compound layer of silicon nitroxide on silicon dioxide in which the atomic concentration fraction of nitrogen falls from a value greater than 0.13 at the top surface of the compound layer to a value of about 0.13 within 30 Angstroms or less beneath the top surface, and advantageously to values of less than about 0.05 everywhere at distances greater than about 60 Angstroms or less beneath the top surface, except that the nitrogen fraction can rise to as much as about 0.10 in the layer at distances within about 20 Angstroms from the interface of the nitrided layer and the underlying semiconductor medium.

Nitrided silicon dioxide layers for semiconductor integrated circuits

A silicon device can be made more resistant to the destructive effects of ionizing radiation by a double annealing; the first annealing to a temperature of the order of 400 degrees C. in hydrogen, the second annealing also to a temperature of 400 degrees C. at a time when the device is not sealed against escape of hydrogen.

Fabrication of semiconductor devices including double annealing steps

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Millington, NJ, United States of America

Avid Kamgar