U.S. Philips Corporation

James E Curran

John C Brice

Christopher A Lawley

Anodising treatments are used to form insulating films (12) in the manufacture of a flat-panel display or other large-area thin-film electronic device. A first film (1,101) of anodisable material (e.g Al) is anodised through a part of its thickness to form an anodic second film (2). A mask pattern (4), e.g of photoresist, is provided at least on the second film (2) to define an area (5) where the second film (2) is etched away through at least a part of its thickness and where a further anodising step is carried out to form an anodic third film (3) contiguous with a remaining part of the anodic second film (2). The manufacture is simplified by using reverse-anodising in an electrolyte solution (20) to carry out the etching of the second film (2). The first film (1,101) is biased negatively as a cathode to carry out the reverse-anodising, after which the further anodising step is carried out by biasing the first film (1,101) positively as an anode in the same electrolyte solution (20) to form the anodic third film (3). A remaining part (11a, 11b) of the first film (1) may provide a conductor track or gate electrode over which there is an insulating film (12) comprising a part of the anodic second film (2) on top of the track/electrode (11a, 11b) and a part of the anodic third film (3) on a sloping side-wall of the track/electrode (11a, 11b). A crossing track (C2,18) or TFT channel region 15 may be deposited over the insulated track/electrode (11a, 11b).

Thin film transistor films made with anodized film and reverse-anodized

In manufacturing an electronic device comprising a thin-film circuit having semiconductor circuit elements (TFTs T1 & T2) processing limitations for the provision of the semiconductor film (1) and regions (5 & 6) of the semiconductor circuit elements are avoided by:

Manufacture of electronic devices comprising thin-film circuits using a

A piezoelectric device comprising a housing that contains a piezoelectric body bearing aluminum film electrodes. The exposed surfaces of the electrodes bear a passivating layer of amorphous aluminum oxide formed by heating the electrodes at a temperature between 250.degree. and 550.degree. C. in an atmosphere containing free oxygen.

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Haywards Heath, United Kingdom

James E Curran