Semiconductor device and manufacturing method thereof
First Claim
1. A method for manufacturing a semiconductor device, comprising the steps of:
- forming an oxide semiconductor layer including crystals at least in a channel formation region wherein the crystals are c-axis-oriented in a direction substantially perpendicular to a surface of the oxide semiconductor layer;
forming a gate insulating layer over the oxide semiconductor layer;
forming a gate electrode over the gate insulating layer;
adding at least one element selected from Group 15 elements to regions of the oxide semiconductor layer with the use of the gate electrode as a mask so that a source region and a drain region are formed, andperforming a heat treatment after the adding step so that the source region and the drain region of the oxide semiconductor layer obtains a wurtzite crystal structure,wherein the oxide semiconductor layer comprises zinc, indium, and gallium.
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Abstract
A semiconductor device capable of high speed operation is provided. Further, a semiconductor device in which change in electric characteristics due to a short channel effect is hardly caused is provided. An oxide semiconductor having crystallinity is used for a semiconductor layer of a transistor. A channel formation region, a source region, and a drain region are formed in the semiconductor layer. The source region and the drain region are formed by self-aligned process in which one or more elements selected from Group 15 elements are added to the semiconductor layer with the use of a gate electrode as a mask. The source region and the drain region can have a wurtzite crystal structure.
178 Citations
27 Claims
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1. A method for manufacturing a semiconductor device, comprising the steps of:
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forming an oxide semiconductor layer including crystals at least in a channel formation region wherein the crystals are c-axis-oriented in a direction substantially perpendicular to a surface of the oxide semiconductor layer; forming a gate insulating layer over the oxide semiconductor layer; forming a gate electrode over the gate insulating layer; adding at least one element selected from Group 15 elements to regions of the oxide semiconductor layer with the use of the gate electrode as a mask so that a source region and a drain region are formed, and performing a heat treatment after the adding step so that the source region and the drain region of the oxide semiconductor layer obtains a wurtzite crystal structure, wherein the oxide semiconductor layer comprises zinc, indium, and gallium. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for manufacturing a semiconductor device, comprising the steps of:
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forming an oxide semiconductor layer including crystals at least in a channel formation region wherein the crystals are c-axis-oriented in a direction substantially perpendicular to a surface of the oxide semiconductor layer; forming a gate insulating layer over the oxide semiconductor layer; forming a gate electrode over the gate insulating layer; adding at least one element selected from Group 15 elements to first regions of the oxide semiconductor layer with the use of the gate electrode as a mask in a first addition step; forming a sidewall on a side surface of the gate electrode; adding at least one element selected from Group 15 elements to second regions of the oxide semiconductor layer with the use of the gate electrode and the sidewall as masks in a second addition step so that a source region, a drain region, a first low-concentration region and a second low-concentration region are formed; and heating the oxide semiconductor layer thereby forming a wurtzite crystal structure in the source region and the drain region of the oxide semiconductor layer, wherein the oxide semiconductor layer comprises zinc, indium, and gallium. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method for manufacturing a semiconductor device, comprising the steps of:
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forming an oxide semiconductor layer including crystals at least in a channel formation region wherein the crystals are c-axis-oriented in a direction substantially perpendicular to a surface of the oxide semiconductor layer; forming a gate insulating layer over the oxide semiconductor layer; forming a gate electrode over the gate insulating layer; adding at least one element selected from Group 15 elements to regions of the oxide semiconductor layer with the use of the gate electrode as a mask so that a source region and a drain region are formed; and performing a heat treatment during the adding step so that the source region and the drain region of the oxide semiconductor layer obtains a wurtzite crystal structure, wherein the oxide semiconductor layer comprises zinc, indium, and gallium. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27)
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Specification