Field effect transistor and method for manufacturing semiconductor device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorYasuhiko TAKEMURA
Life of this patent
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Abstract
A structure with which the zero current of a field effect transistor using a conductor-semiconductor junction can be reduced is provided. A floating electrode (102) including a conductor or a semiconductor and being enclosed by an insulator (104) is formed between a semiconductor layer (101) and a gate (105) so as to cross the semiconductor layer (101) and the floating electrode (102) is charged, whereby carriers are prevented from flowing from a source electrode (103a) or a drain electrode (103b). Accordingly, a sufficiently low carrier concentration can be kept in the semiconductor layer (101) and thus the zero current can be reduced.
Claims12
A field effect transistor comprising:
- a semiconductor layer;
- first and second conductor electrodes in contact with a first surface of the semiconductor layer;
- a gate over the first surface or a second surface of the semiconductor layer;
- and
- a floating electrode between the semiconductor layer and the gate,
- wherein the floating electrode comprises a conductor or a semiconductor, is enclosed by an insulator, and is charged with a predetermined electric charge,
- wherein the floating electrode is provided so as to cross the semiconductor layer, and
- wherein no PN junction exists in the field effect transistor.
A field effect transistor comprising:
- a semiconductor layer;
- first and second conductor electrodes in contact with a first surface of the semiconductor layer;
- a gate over the first surface or a second surface of the semiconductor layer;
- and
- a floating electrode between the semiconductor layer and the gate,
- wherein the floating electrode comprises a conductor or a semiconductor, is enclosed by an insulator, and is charged with a predetermined electric charge,
- wherein the floating electrode is provided so as to cross the semiconductor layer, and
- wherein a conductor-semiconductor junction exists between each of the first and second conductor electrodes and the semiconductor layer.
A method for manufacturing a semiconductor device, comprising the steps of:
- forming a semiconductor circuit comprising a field effect transistor wherein the field effect transistor comprising:
- a semiconductor layer;
- first and second conductor electrodes in contact with a first surface of the semiconductor layer;
- a gate over the first surface or a second surface of the semiconductor layer;
- and
- a floating electrode between the semiconductor layer and the gate,
- wherein the floating electrode comprises a conductor or a semiconductor and is enclosed by an insulator, and
- wherein the floating electrode is provided so as to cross the semiconductor layer;
- charging the floating electrode;
- and
- covering the semiconductor circuit with a light-blocking material after the step of charging the floating electrode.
A method for manufacturing a semiconductor device, comprising the steps of:
- forming a semiconductor circuit comprising a pad, and a field effect transistor wherein the field effect transistor comprises:
- a semiconductor layer;
- first and second conductor electrodes in contact with a first surface of the semiconductor layer;
- a gate over the first surface or a second surface of the semiconductor layer;
- and
- a floating electrode between the semiconductor layer and the gate,
- wherein the floating electrode comprises a conductor or a semiconductor and is enclosed by an insulator, and
- wherein the floating electrode is provided so as to cross the semiconductor layer;
- and
- charging the floating electrode by applying voltage to the gate and one of the first and second conductor electrodes through the pad.
Dependencies are inferred from the claim text.