SEMICONDUCTOR ELEMENT AND METHOD FOR MANUFACTURING THE SAME
First Claim
Patent Images
1. A method for manufacturing an oxide semiconductor element comprising the steps of:
- forming a gate electrode over a substrate;
forming a gate insulating film over the gate electrode;
forming an oxide semiconductor layer over the gate electrode with the gate insulating film therebetween;
forming a source electrode and a drain electrode, the source electrode and the drain electrode are in contact with the oxide semiconductor layer and end portions of the source electrode and the drain electrode overlap with the gate electrode; and
forming an oxide insulating layer covering the oxide semiconductor layer between the source electrode and the drain electrode,wherein the substrate is held in a first reaction chamber kept in a reduced pressure state,wherein the substrate is heated to a temperature lower than or equal to 600°
C.,wherein the gate insulating film is formed over the substrate by introducing a sputtering gas while moisture remaining in the first reaction chamber is removed, and using a first target provided in the first reaction chamber, andwherein the oxide semiconductor layer is formed over the gate insulating film by using a metal oxide provided in a second reaction chamber as a second target.
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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.
89 Citations
20 Claims
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1. A method for manufacturing an oxide semiconductor element comprising the steps of:
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forming a gate electrode over a substrate; forming a gate insulating film over the gate electrode; forming an oxide semiconductor layer over the gate electrode with the gate insulating film therebetween; forming a source electrode and a drain electrode, the source electrode and the drain electrode are in contact with the oxide semiconductor layer and end portions of the source electrode and the drain electrode overlap with the gate electrode; and forming an oxide insulating layer covering the oxide semiconductor layer between the source electrode and the drain electrode, wherein the substrate is held in a first reaction chamber kept in a reduced pressure state, wherein the substrate is heated to a temperature lower than or equal to 600°
C.,wherein the gate insulating film is formed over the substrate by introducing a sputtering gas while moisture remaining in the first reaction chamber is removed, and using a first target provided in the first reaction chamber, and wherein the oxide semiconductor layer is formed over the gate insulating film by using a metal oxide provided in a second reaction chamber as a second target. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for manufacturing an oxide semiconductor element comprising the steps of:
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forming a gate electrode over a substrate; forming a gate insulating film over the gate electrode; forming an oxide semiconductor layer over the gate electrode with the gate insulating film therebetween; forming a source electrode and a drain electrode, the source electrode and the drain electrode are in contact with the oxide semiconductor layer and end portions of the source electrode and the drain electrode overlap with the gate electrode; and forming an oxide insulating layer covering the oxide semiconductor layer between the source electrode and the drain electrode, wherein the substrate over which the gate insulating film is formed is held in a heat chamber kept in a reduced pressure state, wherein the substrate is preheated to a temperature lower than or equal to 400°
C. while moisture remaining in the heat chamber is removed,wherein the substrate is held in a reaction chamber kept in a reduced pressure state, wherein the substrate is heated to a temperature lower than or equal to 600°
C., andwherein the oxide semiconductor layer is formed over the gate insulating film by using a metal oxide provided in the reaction chamber as a target. - View Dependent Claims (8, 9, 10, 11)
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12. A thin film transistor comprising:
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a gate electrode over a substrate; a gate insulating film over the gate electrode; an oxide semiconductor layer over the gate electrode with the gate insulating film therebetween; a source electrode and a drain electrode, the source electrode and the drain electrode are in contact with the oxide semiconductor layer and end portions of the source electrode and the drain electrode overlap with the gate electrode; and an oxide insulating layer covering the oxide semiconductor layer formed between the source electrode and the drain electrode, wherein hydrogen concentration at an interface between the oxide semiconductor layer and the oxide insulating layer is more than or equal to 5×
1019 cm−
3 and less than or equal to 1×
1022 cm−
3. - View Dependent Claims (13, 14)
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15. A thin film transistor comprising:
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a gate electrode over a substrate; a gate insulating film over the gate electrode; an oxide semiconductor layer over the gate electrode with the gate insulating film therebetween; a source electrode and a drain electrode, the source electrode and the drain electrode are in contact with the oxide semiconductor layer and end portions of the source electrode and the drain electrode overlap with the gate electrode; and an oxide insulating layer covering the oxide semiconductor layer formed between the source electrode and the drain electrode, wherein hydrogen concentration at an interface between the oxide semiconductor layer and the oxide insulating layer is more than or equal to 5 times and less than or equal to 100 times as high as hydrogen concentration in a portion of the oxide insulating layer apart from the interface by 30 nm. - View Dependent Claims (16, 17)
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18. A thin film transistor comprising:
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a gate electrode over a substrate; a gate insulating film over the gate electrode; an oxide semiconductor layer over the gate electrode with the gate insulating film therebetween; a source electrode and a drain electrode, the source electrode and the drain electrode are in contact with the oxide semiconductor layer and end portions of the source electrode and the drain electrode overlap with the gate electrode; and an oxide insulating layer covering the oxide semiconductor layer formed between the source electrode and the drain electrode, wherein hydrogen concentration in the oxide insulating layer is more than or equal to 1×
1018 cm−
3 and less than or equal to 2×
1020 cm−
3. - View Dependent Claims (19, 20)
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Specification
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Current AssigneeSemiconductor Energy Laboratory Co., Ltd.
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Original AssigneeSemiconductor Energy Laboratory Co., Ltd.
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InventorsMIYANAGA, Akiharu, KOEZUKA, Junichi, IMOTO, Yuki, SAKAKURA, Masayuki, SAKATA, Junichiro, MARUYAMA, Tetsunori, YAMAZAKI, Shunpei
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Granted Patent
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Time in Patent OfficeDays
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Field of Search
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US Class Current257/43
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CPC Class CodesH01L 21/02565 Oxide semiconducting materi...H01L 27/1225 with semiconductor material...H01L 29/66969 of devices having semicondu...H01L 29/7869 having a semiconductor body...
