JPH027420A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To enhance a characteristic of a part to be hydrogenated without deteriorating a characteristic of an amorphous silicon part by a method wherein the part to be hydrogenated is formed on a substrate, this part to be hydrogenated is treated with a hydrogen plasma and hydrogenated and, after that, the amorphous silicon part is formed. CONSTITUTION:A part 1 to be hydrogenated and electrodes 9a, 9b are formed; after that, the part 1 to be hydrogenated is treated with a hydrogen plasma. Thereby, a trap density of polycrystalline silicon films 3, 3 constituting the part 1 to be hydrogenated is reduced; an electrical characteristic and a photoelectric characteristic such as a mobility mu of a carrier, a lifetime tau and the like and the generation of a leakage current are suppressed; a characteristic of the part 1 to be hydrogenated can be enhanced. Then, an amorphous silicon part 10 can be formed easily by a plasma CVD method. The amorphous silicon part 10 formed in the manner is formed as a sensor part displaying a function as a photoelectric transducer part of a line sensor.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for manufacturing a semiconductor device provided with a portion to be hydrogenated and an amorphous silicon portion, and particularly relates to a method for manufacturing a semiconductor device comprising a polycrystalline silicon film. The present invention relates to a method of manufacturing a semiconductor device suitable for use in manufacturing a semiconductor device such as a line sensor having a MOS type thin film transistor and an amorphous silicon portion.

[Summary of the invention]

The present invention provides a method for manufacturing a semiconductor device having both a portion to be hydrogenated and an amorphous silicon portion, in which the portion to be hydrogenated is first formed on a substrate, and the portion to be hydrogenated is subjected to hydrogen plasma treatment. By forming an amorphous silicon part after hydrogenation, it is possible to improve the characteristics of the part to be hydrogenated without deteriorating the characteristics of the amorphous silicon part, and also to improve the yield and reduce the number of manufacturing steps. The purpose of this invention is to provide a method for manufacturing a semiconductor device that can perform the following steps.

[Conventional technology]

When the active layer of a semiconductor device consisting of a thin film transistor is composed of a polycrystalline silicon film, many traps exist in this polycrystalline silicon film, so electrical characteristics such as carrier mobility μ and life time τ are affected. There are disadvantages such as poor photoelectric properties and generation of leakage current. Therefore, hydrogenation treatment is performed on the polycrystalline silicon film to reduce the trap density within the polycrystalline silicon film, thereby improving the electrical and photoelectric characteristics of the polycrystalline silicon film and preventing the occurrence of leakage current. has traditionally been carried out.

For example, as a method of hydrogenating the polycrystalline silicon film, as described in JP-A-61-46069, the polycrystalline silicon film is subjected to hydrogen plasma treatment, and then the polycrystalline silicon film is There is a method of forming a silicon nitride film and performing heat treatment. In addition, as another hydrogenation treatment method, a silicon nitride film or amorphous silicon film containing hydrogen is formed on a polycrystalline silicon film, and the silicon nitride film or amorphous silicon film itself is used as a hydrogen diffusion source. Another method involves hydrogenation by heat treatment at high temperatures.

[Problem to be solved by the invention]

By the way, for example, there is a semiconductor device, such as a line sensor, in which a polycrystalline silicon film that constitutes a drive circuit section, that is, a section to be hydrogenated, and an amorphous silicon section that constitutes a part of the sensor are both on the same substrate. . Conventionally,
In manufacturing this semiconductor device, after forming a hydrogenated part and an amorphous silicon part on a substrate, a hydrogen-containing silicon nitride film is formed on the hydrogenated part and annealed at high temperature. Hydrogen was then diffused from the silicon nitride film into the area to be hydrogenated.

However, the amorphous silicon portion that constitutes a part of the sensor of the semiconductor device has low heat resistance, and has a characteristic of releasing hydrogen contained in the amorphous silicon when the temperature reaches 150° C. or higher, for example. . Therefore, after forming the part to be hydrogenated and the amorphous silicon part, hydrogen is diffused into the part to be hydrogenated by annealing the silicon nitride film containing hydrogen at a high temperature, for example, 350°C, as described above. In this case, there is a problem that the hydrogen contained in the amorphous silicon portion is released, and the characteristics of the amorphous silicon portion are rapidly deteriorated.

Furthermore, in the method of manufacturing a semiconductor device as described above,
It is necessary to remove the hydrogen-containing silicon nitride film formed to hydrogenate the portion to be hydrogenated after hydrogenation, which increases the number of manufacturing steps of the semiconductor device and makes the manufacturing process complicated. there were.

Furthermore, in order to remove the silicon nitride film used in the hydrogenation process, it is necessary to move the wafer to a device for removing the silicon nitride film that is separate from the device for the hydrogenation process. There is also a possibility that contamination may occur, leading to a decrease in yield.

Therefore, the present invention has been proposed in view of the above-mentioned conventional situation, and when manufacturing a semiconductor device having both a hydrogenated portion and an amorphous silicon portion, it is possible to avoid deteriorating the characteristics of the amorphous silicon portion. It is an object of the present invention to provide a method for manufacturing a semiconductor device that can improve the characteristics of a portion to be hydrogenated, as well as improve yield and reduce the number of manufacturing steps.

[Means to solve the problem]

The present invention has been proposed to achieve the above object, and includes a method for manufacturing a semiconductor device having both a hydrogenated portion and an amorphous silicon portion, which includes forming the hydrogenated portion on a substrate. The method is characterized by comprising a step, a step of performing hydrogen plasma treatment to hydrogenate the portion to be hydrogenated, and a step of forming the amorphous silicon portion.

Here, the semiconductor device according to the manufacturing method of the present invention has a hydrogenated portion that can be hydrogenated by hydrogen plasma treatment to improve its characteristics. An example of this hydrogenated portion is a thin film transistor whose active layer is formed of polycrystalline silicon. Further, this semiconductor device has an amorphous silicon portion formed of amorphous silicon. One example of this is the use of this amorphous silicon portion as part of a sensor that senses incident light and converts it into electricity.

The semiconductor device according to the manufacturing method of the present invention is a semiconductor device in which the hydrogenated portion and the amorphous silicon portion are formed on the same substrate. Examples include devices such as line sensors and area sensors in which the amorphous silicon part functions as a part of the sensor.

In the method for manufacturing a semiconductor device described above, the hydrogenation treatment target portion is subjected to hydrogenation treatment using a hydrogen plasma method. Furthermore, the hydrogen plasma treatment step for the hydrogenated portion and the formation step for the amorphous silicon portion can be performed in the same plasma CVD apparatus by simply changing the formation conditions.

[Effect]

In a method for manufacturing a semiconductor device in which a portion to be hydrogenated and an amorphous silicon portion are formed on the same substrate, the portion to be hydrogenated is subjected to hydrogen plasma treatment before forming the amorphous silicon portion, which has poor heat resistance. Since the hydrogenation treatment is performed, it is possible to improve the characteristics of the hydrogenated portion without degrading the characteristics of the amorphous silicon portion.

In addition, in the method for manufacturing a semiconductor device described above, the hydrogen plasma treatment process of the hydrogenated part and the formation process of the amorphous silicon part can be performed in the same equipment, so there is no risk of contamination with impurities and the yield can be improved. Improvements can be made.

Furthermore, the manufacturing process can be simplified since the conventional process of forming and removing a silicon nitride film used in hydrogenation treatment is eliminated.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a method for manufacturing a semiconductor device according to the present invention is applied to manufacturing a line sensor will be described below with reference to the drawings.

First, as shown in FIG. 1, a hydrogenated portion 1 constituting a thin film transistor having a polycrystalline silicon film 3.5 as an active layer is formed on an insulating substrate 2 by a conventional method.

As shown in FIG. 1, the hydrogenated portion 1 is formed by implanting impurities into the insulating substrate 2 to form the source region 6. Polycrystalline silicon film 3 constituting drain region 7 is formed by CVD. Note that the insulating substrate 2 is made of an insulating material such as a glass substrate or an oxide film formed on a glass substrate. Further, in this embodiment, an n-type impurity, for example, P, is ion-implanted into the polycrystalline silicon film 3 to form an n0-type source region 6° and drain region 7.

A SiO□ film 4 and a polycrystalline silicon film 5 are further formed in a laminated manner at predetermined locations of the polycrystalline silicon film 3, and the SiOz film 4 serves as a gate insulating film, and the polycrystalline silicon film 5 also serves as a gate insulating film. constitutes a gate.

A SiO□ film 8 is formed over the entire uppermost layer of the stacked body having such a structure, and in particular, openings 8a are formed at predetermined portions above the source region 6 and drain region 7.

8b is formed with an opening. The hydrogenation treatment section 1 having the above-described configuration functions as a part of the drive circuit section in the line sensor.

Next, electrodes 9a9b are formed by CVD in the openings 8a and 8b formed in predetermined portions of the Sin film 8 formed in the uppermost layer of the hydrogenated portion 1 configured as described above. . The electrodes 9a9b are formed of a material that is normally used as an electrode for this type of semiconductor device, such as a material obtained by doping polysilicon with impurities to give it conductivity. In particular, one electrode 9a is a portion corresponding to a portion where an amorphous silicon portion 10 is formed from an opening 8a in order to establish electrical conduction between the portion to be hydrogenated 1 and the amorphous silicon portion IO to be produced in the next step. It is arranged continuously up to the top of the insulating base 2.

After forming the hydrogenated portion 1 and the electrodes 9a9b as described above, the hydrogenated portion 1 is subjected to hydrogen plasma treatment. This hydrogen plasma treatment is performed by using a plasma CVD device, setting the temperature condition inside the device to 350° C., and performing plasma annealing treatment using hydrogen gas for one hour.

By performing the hydrogen plasma treatment on the hydrogenated portion l in this manner, the trap density of the polycrystalline silicon film 3.5 constituting the hydrogenated portion l is reduced, and the carrier mobility μ Electrical and photoelectrical characteristics such as and life time τ, generation of leakage current, etc. are suppressed, and the characteristics of the hydrogenated portion 1 can be improved.

After hydrogenating the portion 1 to be hydrogenated as described above, an amorphous silicon portion 10 is formed as shown in FIG. This amorphous silicon part 1
0, it is possible to use a plasma CVD apparatus that performs hydrogen plasma treatment on the hydrogenated portion l, and the temperature conditions within the apparatus are set at 250°C to 280°C.
It can be easily formed by a plasma CVD method. The amorphous silicon section 10 formed in this manner is formed as a part of a sensor that functions as a photoelectric conversion section of a line sensor.

Forming the amorphous silicon portion 10 after hydrogen plasma treatment as described above prevents the amorphous silicon portion IO, which has poor heat resistance, from reaching a high temperature state and prevents the characteristics of the amorphous silicon portion 10 from deteriorating. This is to do so.

The hydrogenation process of the hydrogenated portion l, that is, the hydrogen plasma treatment process, and the formation process of the amorphous silicon part 10, that is, the plasma CVD process, are both performed in the same plasma CVD apparatus under the temperature conditions within the apparatus. This can be easily done by simply changing the following. therefore,
Compared to conventional manufacturing methods, the incorporation of impurities can be suppressed and the yield of manufactured semiconductor devices can be improved.

Furthermore, unlike conventional manufacturing methods, this manufacturing method eliminates the need for a silicon nitride film manufacturing process, a removal process, etc., and therefore, it is possible to reduce the number of manufacturing steps for the semiconductor device.

Note that the present invention is not limited to the above-described embodiments, and various modifications based on the technical idea of the present invention are possible, and the present invention can also be applied to other types of semiconductor devices having similar configurations. Can be applied.

(Effects of the Invention) As is clear from the above description, in the method for manufacturing a semiconductor device according to the present invention, before forming the amorphous silicon portion, hydrogen is applied to the hydrogenated portion by hydrogen plasma CVD at a high temperature. Since the hydrogenation treatment is performed, the characteristics of the portion to be hydrogenated can be improved without deteriorating the characteristics of the amorphous silicon.

In addition, since the hydrogenation process of the hydrogenated part and the formation process of the amorphous silicon part can be performed in the same plasma CVD apparatus by simply changing the conditions within the apparatus, there is no risk of contamination with impurities. Yield can be improved.

Furthermore, the manufacturing process can be simplified because the conventional process of forming and removing a silicon nitride film is not necessary.

Therefore, it is possible to provide a method for manufacturing a semiconductor device that can improve the characteristics of the portion to be hydrogenated without deteriorating the characteristics of the amorphous silicon portion, improve the yield, and reduce the number of manufacturing steps. .

[Brief explanation of the drawing]

1 and 2 are schematic cross-sectional views sequentially showing an example of a method for manufacturing a semiconductor device according to the present invention. ■...Hydrogenated section 10...Amorphous silicon section Patent applicant Sony Corporation representative Patent attorney Kodo Koike Jo Yamamura Masaru Sato

Claims (1)

[Claims] A method for manufacturing a semiconductor device having both a hydrogenated portion and an amorphous silicon portion, comprising: forming the hydrogenated portion on a substrate; and performing hydrogen plasma treatment to hydrogenate the hydrogenated portion. A method for manufacturing a semiconductor device, comprising the steps of: hydrogenating a treated portion; and forming the amorphous silicon portion.