SEMICONDUCTOR ELEMENT AND METHOD FOR MANUFACTURING THE SAME
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Accused Products
Abstract
An object is to provide a thin film transistor and a method for manufacturing the thin film transistor including an oxide semiconductor with a controlled threshold voltage, high operation speed, a relatively easy manufacturing process, and sufficient reliability. An impurity having influence on carrier concentration in the oxide semiconductor layer, such as a hydrogen atom or a compound containing a hydrogen atom such as H2O, may be eliminated. An oxide insulating layer containing a large number of defects such as dangling bonds may be formed in contact with the oxide semiconductor layer, such that the impurity diffuses into the oxide insulating layer and the impurity concentration in the oxide semiconductor layer is reduced. The oxide semiconductor layer or the oxide insulating layer in contact with the oxide semiconductor layer may be formed in a deposition chamber which is evacuated with use of a cryopump whereby the impurity concentration is reduced.
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Citations
16 Claims
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1. (canceled)
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2. A method for manufacturing a semiconductor element comprising the steps of:
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forming a gate electrode over a substrate; forming a gate insulating layer over the gate electrode; performing a first heat treatment on the substrate at a temperature lower than or equal to 600°
C. after forming the gate insulating film;forming an oxide semiconductor layer over the gate insulating layer while the substrate is heated at a temperature higher than or equal to 100°
C. and lower than or equal to 600°
C.; andforming an oxide insulating layer over the oxide semiconductor layer by a sputtering method, wherein a part of the oxide insulating layer is in contact with the oxide semiconductor layer. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9)
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10. A method for manufacturing a semiconductor element comprising the steps of:
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forming a gate electrode over a substrate; forming a first wiring over the substrate; forming a first insulating layer over the gate electrode and the first wiring; performing a first heat treatment on the substrate at a temperature lower than or equal to 600°
C. after forming the first insulating layer;forming an oxide semiconductor layer over the first insulating layer while the substrate is heated at a temperature higher than or equal to 100°
C. and lower than or equal to 600°
C.;forming a source electrode and a drain electrode over the oxide semiconductor layer, wherein the source electrode and the drain electrode is electrically connected to the oxide semiconductor layer; forming a second wiring over the first insulating layer, wherein the second wiring is electrically connected to the first wiring through an opening portion in the first insulating layer; and forming a second insulating layer over the oxide semiconductor layer by a sputtering method, wherein at least a part of the second insulating layer is in contact with the oxide semiconductor layer, wherein the gate electrode and the first wiring are formed at the same time, and wherein the source electrode, the drain electrode, and the second wiring are formed at the same time. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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Specification