SEMICONDUCTOR DEVICE CAPABLE OF THRESHOLD VOLTAGE ADJUSTMENT BY APPLYING AN EXTERNAL VOLTAGE
First Claim
1. A method of manufacturing a semiconductor device having gates and junction regions, the method comprising the steps of:
- forming a pad oxide film and a pad nitride film on a silicon substrate having a device isolation region and an active region;
etching the pad oxide film, the pad nitride film, and the silicon substrate to form a trench in the device isolation region;
forming an insulating film spacer on a trench sidewall including the etched pad oxide and nitride films;
laterally etching a portion of the active region in the silicon substrate using the pad oxide film, the pad nitride film, and the insulating film spacer as etch barriers;
removing the insulating film spacer;
forming a conductive electrode on the surface adjoining the laterally etched portion in the active region and on the surface of the trench in the isolation region; and
filling up the trench and the laterally etched portion with an oxide film to form a device isolation film, wherein none or some pockets of vacant cavity is present between the device isolation film and the conductive electrode.
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Abstract
A semiconductor device has a silicon substrate, in which an active region is formed between two device isolation films and a gate is formed on the surface of the active region. The silicon substrate has a laterally etched portion in the active region below the surface of the active region on the side near the device isolation film. An insulating film is formed on the laterally etched portion of the silicon substrate. A conductive electrode is formed on the insulating film, through which an external voltage is applied to adjust a threshold voltage. The device isolation film is formed on the conductive electrode. None or some pockets of vacant cavity is present between the device isolation film and the conductive electrode.
13 Citations
18 Claims
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1. A method of manufacturing a semiconductor device having gates and junction regions, the method comprising the steps of:
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forming a pad oxide film and a pad nitride film on a silicon substrate having a device isolation region and an active region;
etching the pad oxide film, the pad nitride film, and the silicon substrate to form a trench in the device isolation region;
forming an insulating film spacer on a trench sidewall including the etched pad oxide and nitride films;
laterally etching a portion of the active region in the silicon substrate using the pad oxide film, the pad nitride film, and the insulating film spacer as etch barriers;
removing the insulating film spacer;
forming a conductive electrode on the surface adjoining the laterally etched portion in the active region and on the surface of the trench in the isolation region; and
filling up the trench and the laterally etched portion with an oxide film to form a device isolation film, wherein none or some pockets of vacant cavity is present between the device isolation film and the conductive electrode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification