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CN-113196501-B - Semiconductor device and method for manufacturing semiconductor device

CN113196501BCN 113196501 BCN113196501 BCN 113196501BCN-113196501-B

Abstract

The invention provides a semiconductor device with less variation of transistor characteristics. A semiconductor device includes a transistor including a first insulator, a first oxide over the first insulator, a first conductor over the first oxide, a second conductor, and a second oxide disposed between the first conductor and the second conductor, a second insulator over the second conductor, and a third conductor over the second insulator, wherein a top surface of the first oxide in a region overlapping the third conductor is lower than a top surface of the first oxide in a region overlapping the first conductor, and a curved surface is provided between a side surface and the top surface of the first oxide in a region overlapping the third conductor, and a radius of curvature of the curved surface is 1nm or more and 15nm or less.

Inventors

  • YAMAZAKI SHUNPEI
  • SASAGAWA SHINYA
  • TOCHIBAYASHI KATSUAKI
  • MURAKAWA TSUTOMU
  • TAKAHASHI ERIKA

Assignees

  • 株式会社半导体能源研究所

Dates

Publication Date
20260505
Application Date
20191119
Priority Date
20181228

Claims (10)

  1. 1. A semiconductor device, comprising: The characteristics of the transistor are that, Wherein the transistor includes: A first insulator; a first oxide on the first insulator; a first conductor, a second conductor, and a second oxide on the first oxide, the second oxide between the first conductor and the second conductor; a second insulator over the second oxide, and A third electrical conductor on the second insulator, A top surface of the first oxide in a region overlapping the third conductor is lower than a top surface of the first oxide in a region overlapping the first conductor, In the region overlapping the third conductor, a curved surface is provided between a side surface and a top surface of the first oxide, The curvature radius of the curved surface is 1nm or more and 15nm or less, In the Id-Vg characteristic of the transistor, the standard deviation sigma of the drift value Vsh of the transistor is less than 60mV, And wherein the standard deviation σ of the drift value Vsh of the transistor is achieved by setting the amount by which the thickness of the first oxide in the region overlapping the third conductor is reduced to be greater than 0nm and 20nm or less.
  2. 2. The semiconductor device according to claim 1, Wherein a difference between a height of a top surface of the first oxide in the region overlapping the third conductor and a height of a top surface of the first oxide in the region overlapping the first conductor is 1nm or more and 5nm or less, based on a bottom surface of the first insulator.
  3. 3. The semiconductor device according to claim 1 or 2, Wherein a half of a difference between a length of a bottom surface of the first oxide in the region overlapping the first conductor and a length of a bottom surface of the first oxide in the region overlapping the third conductor in a channel width direction of the transistor is 2nm or more and 10nm or less.
  4. 4. The semiconductor device according to claim 1, Wherein the transistor comprises a third oxide and a fourth oxide, The third oxide is between the first oxide and the first electrical conductor, The fourth oxide is between the first oxide and the second conductor, And a bottom surface of the second oxide is lower than a bottom surface of the third oxide and a bottom surface of the fourth oxide in a channel length direction of the transistor.
  5. 5. A semiconductor device, comprising: a plurality of the transistors of the transistor array are arranged, Wherein each transistor of the plurality of transistors comprises: A first insulator; a first oxide on the first insulator; a first conductor, a second conductor, and a second oxide on the first oxide, the second oxide between the first conductor and the second conductor; a second insulator over the second oxide, and A third electrical conductor on the second insulator, A top surface of the first oxide in a region overlapping the third conductor is lower than a top surface of the first oxide in a region overlapping the first conductor, In the region overlapping the third conductor, a curved surface is provided between a side surface and a top surface of the first oxide, In the Id-Vg characteristics of the plurality of transistors, the standard deviation sigma of the drift value Vsh of the plurality of transistors is less than 60mV, And wherein the standard deviation σ of the drift values Vsh of the plurality of transistors is achieved by setting the amount by which the thickness of the first oxide in the region overlapping the third conductor is reduced to be greater than 0nm and 20nm or less.
  6. 6. The semiconductor device according to claim 5, Wherein a channel length of each of the plurality of transistors is 40nm or more and 80nm or less, And a channel width of each of the plurality of transistors is 40nm or more and 80nm or less.
  7. 7. The semiconductor device according to claim 5, Wherein the curvature radius of the curved surface is 1nm or more and 15nm or less.
  8. 8. A semiconductor device, comprising: The characteristics of the transistor are that, Wherein the transistor includes: A first insulator; a first oxide on the first insulator; a first conductor, a second conductor, and a second oxide on the first oxide, the second oxide between the first conductor and the second conductor; a second insulator on the second oxide; A third conductor on the second insulator, and A third insulator disposed in contact with a top surface of the first conductor, a top surface of the second conductor, and a part of a side surface of the first oxide, The length of the bottom surface of the first oxide in the region overlapping the first conductor is longer than the length of the bottom surface of the first oxide in the region overlapping the third conductor in the channel width direction of the transistor, In the region overlapping the third conductor, a curved surface is provided between a side surface and a top surface of the first oxide, The first oxide comprises indium, element M and zinc, The element M is any one of gallium, yttrium and tin, The third insulator contains an element that becomes an impurity of the first oxide, The concentration ratio of the element to the element M on the side of the first oxide in the region overlapping the third conductor is smaller than the concentration ratio of the element to the element M on the side of the first oxide in the region overlapping the first conductor, In the Id-Vg characteristic of the transistor, the standard deviation sigma of the drift value Vsh of the transistor is less than 60mV, And wherein the standard deviation σ of the drift value Vsh of the transistor is achieved by setting the amount by which the thickness of the first oxide in the region overlapping the third conductor is reduced to be greater than 0nm and 20nm or less.
  9. 9. The semiconductor device according to claim 8, Wherein the element in the third insulator is aluminum.
  10. 10. The semiconductor device according to claim 8, Wherein the curvature radius of the curved surface is 1nm or more and 15nm or less.

Description

Semiconductor device and method for manufacturing semiconductor device Technical Field One embodiment of the present invention relates to a transistor, a semiconductor device, and an electronic apparatus. Further, one embodiment of the present invention is a method for manufacturing a semiconductor device. Further, one embodiment of the present invention relates to a semiconductor wafer and a module. Note that in this specification and the like, a semiconductor device refers to all devices that can operate by utilizing semiconductor characteristics. In addition to a semiconductor element such as a transistor, a semiconductor circuit, an arithmetic device, or a memory device is one embodiment of a semiconductor device. Display devices (liquid crystal display devices, light-emitting display devices, and the like), projection devices, illumination devices, electro-optical devices, power storage devices, semiconductor circuits, imaging devices, electronic devices, and the like may include semiconductor devices. Note that one embodiment of the present invention is not limited to the above-described technical field. One embodiment of the disclosed invention in this specification and the like relates to an object, a method, or a manufacturing method. In addition, one embodiment of the present invention relates to a process, machine, product, or composition (composition of matter). Background A technique of forming a transistor by using a semiconductor thin film formed over a substrate having an insulating surface is attracting attention. Such a transistor is widely used in electronic devices such as an Integrated Circuit (IC) and an image display device (also simply referred to as a display device). As a semiconductor thin film applicable to a transistor, a silicon-based semiconductor material is widely known. In addition, as other materials, oxide semiconductors are attracting attention. In the oxide semiconductor, a CAAC (c-axis ALIGNED CRYSTALLINE: c-axis oriented crystal) structure and a nc (nanocrystalline: nanocrystalline) structure were found to be neither single crystal nor amorphous (see non-patent documents 1 to 2). Non-patent document 1 and non-patent document 2 disclose a technique for manufacturing a transistor using an oxide semiconductor having a CAAC structure. [ Prior Art literature ] [ Non-patent literature ] [ Non-patent document 1]S.Yamazaki et al ], "SID Symposium Digest of TECHNICAL PAPERS",2012,volume 43,issue 1,p.183-186 [ Non-patent literature ] 2]S.Yamazaki et al.,"Japanese Journal of Applied Physics",2014,volume 53,Number 4S,p.04ED18-1-04ED18-10 Disclosure of Invention Technical problem to be solved by the invention An object of one embodiment of the present invention is to provide a semiconductor device with small variations in transistor characteristics. An object of one embodiment of the present invention is to provide a semiconductor device having a high on-state current. An object of one embodiment of the present invention is to provide a semiconductor device having good electrical characteristics. An object of one embodiment of the present invention is to provide a semiconductor device which can be miniaturized or highly integrated. An object of one embodiment of the present invention is to provide a semiconductor device with excellent reliability. Another object of one embodiment of the present invention is to provide a semiconductor device with low power consumption. Note that the description of these objects does not hinder the existence of other objects. Not all of the above objects need be achieved in one embodiment of the present invention. Objects other than the above objects will be apparent from and can be extracted from the description of the specification, drawings, claims, and the like. Means for solving the technical problems A semiconductor device includes a transistor including a first insulator, a first oxide over the first insulator, a first conductor over the first oxide, a second conductor, and a second oxide disposed between the first conductor and the second conductor, a second insulator over the second conductor, and a third conductor over the second insulator, wherein a top surface of the first oxide in a region overlapping the third conductor is lower than a top surface of the first oxide in a region overlapping the first conductor, a curved surface is provided between a side surface and the top surface of the first oxide in a region overlapping the third conductor, and a radius of curvature of the curved surface is 1nm or more and 15nm or less. In the semiconductor device, it is preferable that a difference between a height of a top surface of the first oxide in a region overlapping the third conductor and a height of a top surface of the first oxide in a region overlapping the first conductor is 1nm or more and 5nm or less, based on a bottom surface of the first insulator. In the semiconductor device, it is preferable that a difference between a length of