JPH05109737A - Manufacture of thin film transistor - Google Patents

Abstract

PURPOSE: To eliminate crystal defect, impurities, etc., from an element activation region, at the time of manufacturing a thin film transistor.

CONSTITUTION: On an insulative substrate 1, an amorphous silicon film 4 is deposited, thereon an oxide film 5 is formed, a photo resist mask 6 which is patterned and formed on the film 5 is us as a mask, and ions are implanted. Thereby only the amorphous silicon film 4 at the part corresponding to a region 3 where an element is not formed is turned into a high impurity region to forin a gettering layer 7. By laser annealing after the photo resist film 6 is eliminated, the amorphous silicon film 4 is crystallized to form a polycrystalline silicon film. At the same time, crystal defect, impurities, etc., in the amorphous silicon film 4 of the part corresponding to an element formation region 2 are made to be absorbed in a high impurity region 7 around the defect and impurities. After that, the oxide film 5 is eliminated, and the polycrystalline silicon film (the gettering layer 7) in unnecessary parts is eliminated by element isolation. In this state, the polycrystalline silicon film is formed only in the element formation region 2 on the insulative substrate 1.

COPYRIGHT: (C)1993,JPO&Japio

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention relates to a method of manufacturing a thin film transistor.

[0002]

The transistor fabrication technology using the Related Art Silicon wafers, using a gettering technique, by removing the crystal defects and impurities from the device active region, so as to obtain the excellent device characteristics. On the other hand, in the thin film transistor manufacturing technology, by isolation after depositing a semiconductor thin film made of amorphous silicon, polysilicon, or the like on an insulating substrate made of glass or the like, since the patterning of the semiconductor thin film in the element formation region, a silicon It can not be utilized gettering technique used in the transistor fabrication technology using wafer.

[0003]

[Problems that the Invention is to Solve As described above, in the conventional thin film transistor manufacturing techniques, it is not possible to use a gettering technique used in the transistor fabrication technology using a silicon wafer, the crystal defects and impurities, etc. can not be removed from the device active region, there is a problem that it may not be possible to obtain thus excellent device characteristics. The purpose of the invention is to provide a method of manufacturing a thin film transistor capable of removing crystal defects and impurities from the device active region.

[0004]

Means for Solving the Problems] The present invention, by depositing a semiconductor thin film in the element forming region and a non-element forming region of the periphery thereof, then only the semiconductor thin film of a portion corresponding to the non-element forming region and the high impurity regions of and a gettering layer, followed by annealing, to absorb the crystal defects and impurities or the like in the semiconductor thin film in the portion corresponding to the element formation region to a gettering layer surrounding, then which was followed by removal of the gettering layer is there.

[0005]

SUMMARY OF] According to the invention, by annealing after the gettering layer only semiconductor thin film of a portion corresponding to the non-element forming region and the high impurity regions of the crystal in the semiconductor thin film of a portion corresponding to the element formation region to absorb defects and impurities such as gettering layer surrounding, since the removal of the gettering layer after this, it is possible to remove the crystal defects and impurities from the device active region.

[0006]

EXAMPLES 1 to 4 shows the manufacturing steps of the thin film transistor in an embodiment of the present invention. Therefore, with reference to the drawings in order to describe a method of manufacturing the thin film transistor.

[0007] First, as shown in FIG. 1, depositing an amorphous silicon film 4 in the non-element forming region 3 of the element formation regions 2 and around the upper surface of the insulating substrate 1 made of glass or the like. Next, by thermal oxidation to form an oxide film 5 on the upper surface of the amorphous silicon film 4. Next, the photoresist film 6 is patterned on the upper surface of the oxide film 5 in the portion corresponding to the element formation region 2. Next, the photoresist film 6 as a mask, phosphorus, boron, argon, oxygen, ions for gettering such as carbon is injected into the amorphous silicon film 4 in the portion corresponding to the non-element forming region 3 by ion implantation apparatus, only the amorphous silicon film 4 in the portion corresponding to the non-element forming region 3 and the high impurity regions of the gettering layer 7
To. Thereafter, the photoresist film is removed 6.

[0008] Next, as shown in FIG. 2, by laser annealing, the amorphous silicon film 4 is crystallized to a polysilicon film 8, the crystals in the amorphous silicon film 4 in the portion corresponding to the element formation region 2 to absorb defects and impurities such as the gettering layer 7 surrounding. Thereafter, to remove the oxide film 5, followed by isolation, the unnecessary polysilicon film 8, that the gettering layer 7 in the portion corresponding to the non-element forming region 3 is removed. Therefore, in this state, the element of the upper surface of the insulating substrate 1 formed region 2
Polysilicon film 8 is formed on only.

[0009] Next, as shown in FIG. 3, a gate insulating film 9 made of silicon oxide or silicon nitride on the entire surface. Then, a gate electrode 11 made of aluminum on the upper surface of the gate insulating film 9 of the portion corresponding to the channel region 10 of the polysilicon film 8 is patterned. Then, the ions for the source and drain formation such as phosphorus or boron is implanted by ion implantation apparatus of the gate electrode 11 as a mask, the polysilicon film 8 on both sides of the gate electrode 11 to form the source and drain regions 12.

[0010] Next, as shown in FIG. 4, an interlayer insulating film 13 made of silicon oxide or silicon nitride on the entire surface. Next, a contact hole 14 in the interlayer insulating film 13 and the gate insulating film 9 of the portion corresponding to the source and drain regions 12. Next, an interlayer source-drain electrodes 15 made of aluminum is connected to the source and drain regions 12 via the contact hole 14 insulating film 13
Patterning the upper surface. Thus, the thin film transistor is manufactured.

[0011] In such a thin film transistor manufactured in the, by annealing after the gettering layer 7 only amorphous silicon film 4 in the portion corresponding to the non-element forming region 3 and the high impurity region of the element formation region 2
The crystal defects and impurities and the like in the amorphous silicon film 4 in the portion corresponding to the absorbed gettering layer 7 surrounding, since the removal of the gettering layer 7 Thereafter, the crystal defects and impurities from the device active region it can be removed, can be obtained and thus excellent device characteristics. Further, one of the annealing process, the amorphous silicon film 4 is crystallized at the same time as the polysilicon film 8, the periphery of gettering the crystal defects and impurities and the like in the amorphous silicon film 4 in the portion corresponding to the element formation region 2 can be absorbed into the layer 7, also by the element isolation,
Since removal of the unnecessary polysilicon film 8, that the gettering layer 7 in the portion corresponding to the non-element forming region 4, the number of steps can be prevented as much as possible increases. Moreover, if in using the same ion as the ion for the source and drain formed as ions for gettering can be performed implantation of ions for gettering by the ion implantation apparatus for source and drain formation.

[0012] In the above embodiment, an amorphous silicon film 4 deposited on the upper surface of the insulating substrate 1 is a polycrystalline silicon film 8 is crystallized, not limited thereto, directly deposited polysilicon film on the upper surface of the insulating substrate it may be. Further, instead of the ion implantation apparatus, a thermal diffusion method may be used, also in place of the laser annealing may be subjected to high-temperature heat treatment. Further, not limited to the coplanar type thin film transistor, it can be applied to staggered thin film transistor.

[0013]

As described in the foregoing, according to the present invention, by annealing after the gettering layer only semiconductor thin film of a portion corresponding to the non-element forming region and the high impurity region of, the element formation region the corresponding crystal defects and impurities in the semiconductor thin film portions such as is absorbed into the gettering layer surrounding, since the removal of the gettering layer after this, it is possible to remove the crystal defects and impurities from the device active region , it can be obtained and thus excellent device characteristics.

BRIEF DESCRIPTION OF THE DRAWINGS

[1] In the production of a thin film transistor according to an embodiment of the present invention, the upper surface of the insulating substrate to form an amorphous silicon film and the oxide film, the more ions for gettering a photoresist film patterned on its upper surface as a mask It injected sectional view of a state of forming the gettering layer.

[2] In the production of the thin film transistor, by laser annealing after removing the photoresist film, the crystal defects in the amorphous silicon film in the portion corresponding to the element formation regions with an amorphous silicon film is crystallized to a polysilicon film sectional view of the state of being absorbed or impurities such as the gettering layer surrounding.

[3] In the production of the thin film transistor, the oxide film and the unnecessary polysilicon film (gettering layer) forming a gate insulating film and a gate electrode after removal of further ions for the source and drain formation of the gate electrode as a mask sectional view of injecting a state in which a source-drain region.

[4] In the production of the thin film transistor, an interlayer insulating film, cross-sectional view of a state of forming contact holes and source and drain electrodes.

DESCRIPTION OF SYMBOLS

1 insulating substrate 2 element forming region 3 non element forming region 4 the amorphous silicon film 5 oxide film 7 gettering layer 8 polysilicon film

Claims (1)

[The claims]
1. 1. A deposit a semiconductor thin film in the element forming region and a non-element forming region of the periphery thereof, then the gettering layer and the high impurity region of only the semiconductor thin film in a portion corresponding to the non-element forming region, then by annealing, the said portion corresponding to the element formation region semiconductor crystal defects in thin films and impurities absorbed on the gettering layer surrounding, then the thin film transistor and removing the gettering layer Production method.