JPH02197177A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To manufacture a semiconductor device excellent in characteristics and small in dispersion of characteristics by a method wherein a fine crystal film is formed on an insulating film and an opening of a substrate, and the fine crystal film is selectively re-crystallized to form a flat semiconductor layer uniform in the direction in parallel with the substrate without degrading crystal grains in diameter. CONSTITUTION:A fine crystal film 13 is formed on an insulating film 7 and an opening 8 provided onto a substrate 6 though a CVD method. That is, when the film 13 is formed, the fine crystal film is uniformly formed on the insulating film 7 and inside the opening 8. And, laser rays are concentrated so as to position their focal point at a position just above the insulating film 7 and made to scan in parallel with the substrate 6 to enable only a fine crystal film 13a on the film 7 to be fused and re-crystallized. A p layer 9 is formed on a re-crystallized part 14 and a fine crystal part 13b through a liquid growth method. And, as the p layer 9 is made to grow making the re-crystallized part 14 and the fine crystal part 13b serve as nucleuses, the growth or the p layer 9 advances uniformly in parallel with the substrate and the surface of the grown p layer 3 becomes flat. As the p layer is formed flat, n flat active layer 2 uniform in a joining property throughout its whole face can be formed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a semiconductor device, and in particular to a method for manufacturing a semiconductor device.
The present invention relates to a method for forming the active layer of (a) flat, uniformly, and with high productivity.

[Conventional technology]

Figure @2 is a schematic diagram schematically showing the basic structure of solar TA micelles.

The solar cell Itl has an active layer (2) and a pole (3) on the surface side.
) and back side 1! [14] Consists of 1 parts.

The incident light tsr is absorbed by the active layer (2), and optical energy is first converted into electrical energy. Active layer (
The electrical energy converted from light energy in step 21 is
It is taken out as an output to the outside through the hexagonal side ε and the backside electrode +31.14).

FIG. 3 shows an example of a conventional method for manufacturing a semiconductor device. For example, Proceedings of 18th I
EEKPhotovoltaic 5specialis
ts Conference-1985.

192 to 97 are cross-sectional views showing the method for manufacturing a polycrystalline Si thin film solar cell in the order of steps.

In the figure, (6) is a metal-grade Si substrate (hereinafter abbreviated as "substrate"), which is the substrate of the entire solar cell fi+ and is also the back surface @aw (FIG. 3 1a)). Substrate [6
) Upper 1c thermal CVD method Niyori 5i02 film (7)c below,
An insulating film) is formed (FIG. 3 1bl). This is to prevent impurity diffusion from the substrate (6) that would adversely affect the characteristics of the active layer 121. However, insulating film 1
Since the active layer 71 does not have a single conductivity, an opening (8) is formed in a part of the insulating film 17+ by selective etching.
) and the board (6) (FIG. 3, 1hl). Since impurity diffusion occurs from the substrate (6) in the opening (8), the number and size of the openings should be 1 to 4.
I'll stop it for a while. In this example, circular openings with a diameter of 200 μm are formed with a distance of 2 mm between adjacent openings.

A p-type polycrystalline Si layer (hereinafter abbreviated as p layer) is formed on the insulating film 171 8 and on the substrate (6) in the opening (8) by liquid phase growth.
(9) is formed (FIG. 3, 1hl to 1gl). Polycrystalline Si grows easily on the substrate (6), but the insulating film 17)
It is difficult to grow at the top. Therefore, the growth first fills the opening (8) and then spreads laterally to cover the insulating film 17). Therefore, large irregularities occur on the surface of the p-layer (9) after growth. Next, an n-type microcrystalline Si layer c (hereinafter referred to as n layer) αQ is formed on the p layer (9) by plasma CVD (FIG. 3, 1hl). In this example, the p layer (9) $5 and the n layer QQ are the active layer (
This corresponds to the second time. Photo-excited carriers (electrons and holes) are generated by the optical energy of the incident light +51 absorbed by the p-layer (9) or the n-layer αQ. And p layer (9), n
From the pn junction between the layers GO, electrons are transported to the n layer (nc) and holes are transported to the p layer (9), where they are converted into electrical energy.

ITO (oxide of In and Sn) / 5nOt transparent 21E film (hereinafter referred to as
A transparent electrode (abbreviated as "transparent electrode") is formed (FIG. 3, 1it). This transparent electrode θυ is a part of the front side electrode (3) and also has the role of an antireflection film. Finally, an Ag/Ti metal electrode film C is formed on the transparent a-pole by electron beam evaporation. (abbreviated as pole) 02 is patterned (third diagram)). Transparent pole 0υ and metal electrode Q
2 acts as a surface@electrode (3).

Through the above steps, a polycrystalline St thin film solar cell Il+ is formed using the method of manufacturing a semiconductor device according to this embodiment.

[Problem to be solved by the invention]

For the polycrystalline St thin film solar cell using the conventional semiconductor device manufacturing method, the insulation film 17) and the opening (
A p layer (9) is formed directly on the substrate (6) of 8),
Polycrystalline Si, which is the material of the p-layer (9), grows easily on the substrate (6) in the opening (8) but does not grow easily on the insulating film 17). A p-layer (9) is formed. Active layer (2) formed by forming n-layer Ql on p-layer (9) with large surface irregularities like this
The bonding characteristics are non-uniform with a 5-layer distribution in the parallel direction to the substrate, and the p layer (9)'s3 and the 1 layer α
It is very difficult to form 0 to the optimum thickness. In addition, even after forming the n-layer αq and the transparent electrode 0υ, surface irregularities remain, making it difficult to form a pattern such as the line width and edge height of the metal electrode O″4.

The present invention was developed to solve the above-mentioned problems, and is particularly suitable for active layers of thick-width batteries. An object of the present invention is to obtain a method for manufacturing a semiconductor device that can form a flat and uniform semiconductor layer with high productivity.

[Means to solve the problem]

A method for manufacturing a semiconductor device according to the present invention includes forming an insulating film having selectively provided openings on a substrate, and forming a semiconductor layer on the insulating film and on the substrate in the opening. The manufacturing method 1 includes the steps of forming a microcrystalline film on the insulating film and the substrate in the opening, and selectively recrystallizing the microcrystalline film.

[Operation] According to the present invention, a microcrystalline film is formed on the insulating film formed on the substrate and on the substrate in the opening, and after selectively recrystallizing the microcrystalline film, the microcrystalline film is selectively recrystallized. Since a semiconductor layer is to be formed, almost the entire exposed surface becomes a growth nucleus, and the semiconductor layer is uniformly formed in one direction parallel to the substrate. As a result, the characteristics of the semiconductor layer become uniform over the entire surface, and the surface becomes flat. In addition, since the microcrystalline film is selectively recrystallized, the grain size of the active layer is maintained and is not impaired. Therefore, when four semiconductor devices are formed under the same conditions, variations in their characteristics can be kept small.

〔Example〕

An embodiment of the present invention will be explained below with reference to the drawings. 0 @1 Figure 1 shows a method for manufacturing a polycrystalline silicon thin film using an embodiment of the method for manufacturing a semiconductor device according to the present invention in the order of steps. FIG.

In the figure, Ill-04 are the same or corresponding parts to the parts 8 in FIGS. 2 and 3 indicated by the same reference numerals. □□□ is on the insulating film 17) and on the substrate (8) in the opening (8)
6) p-type machine crystalline Si film (hereinafter abbreviated as microcrystalline film) formed at 2000A8 degrees by the first plasma CVD method;
A4 is a region where this microcrystalline film is selectively recrystallized (hereinafter abbreviated as recrystallized region).

The formation of the insulating film (7) on the substrate (6) and the formation of the opening (8) are the same as in the conventional embodiments (FIG. 1, 1al to 1).
Ic1 isolation @ membrane 17) top 8 and substrate (6) of opening (8)
Microcrystalline go3 (insulating film 12 (t3a)) is formed on top by plasma CVD.

An opening (x3b) is formed (FIG. 1 1d)). If the plasma CVD method is used, a uniform film can be formed over the entire exposed surface. If the microcrystalline film 03 is formed from this, the microcrystalline film is formed uniformly over the insulating film 17) and the opening (8). Microcrystal I11! For the formation of (2), it is sufficient to obtain a film thickness that can serve as a growth nucleus when forming the p layer (9).

As it is, the grain size of the microcrystalline film 03 is always small.

If a p-layer (9) is formed on this microcrystalline film 01 without any treatment, the p-layer (9) will grow using the microcrystalline film (to) as a nucleus, so the grain size of the p-layer (9) will be will also become smaller. If the grain size is small, recombination of carriers at grain boundaries increases, making it impossible to efficiently extract photoexcited carriers. p
In order to ensure the grain size of the layer (9), it is necessary to increase the grain size of the microcrystalline film a, which forms the core thereof. In this Example 2, the grain size is increased by melting the microcrystalline film by laser annealing and recrystallizing it. However, for the microcrystalline film (13b) in the opening (8), the high temperature associated with melting promotes impurity diffusion from the substrate (6). Taking this into consideration, melting and recrystallization are performed on the microcrystalline film (1ab) on the insulating film 171, but not on the microcrystalline film (t: (a) l) on the opening (8). Hereinafter, 1t3b) will be referred to as the microcrystalline part). The laser beam is focused so that the height directly above the insulating film +71 is focused, and the laser beam is scanned parallel to the substrate (6).
Only the microcrystalline film (t3a) on 71 is melted and recrystallized (@1 Figure 1el).

A p-layer (9) is formed on the recrystallized part α and the microcrystalline part (13b) by the liquid phase growth method (FIG. 1h1.
Igl).

The p layer (9) has a recrystallized part α41i3 and a microcrystalline part (ta
Since it grows using b) as a nucleus, uniform growth progresses in the direction parallel to the substrate (the substrate), and the surface of the p layer (9) after formation becomes flat.

The formation of the n-layer layer, the formation of the transparent electrode 0υ, and the formation of the pattern of the metal electrode are the same as in the conventional embodiment described above (see FIG. 1).
h1. +jl).

Since the p layer (9) is formed flat, a flat active layer (2) with uniform bonding characteristics over the entire surface is formed. Thereby, the p layer (9) and the n layer at1 can be easily formed to the optimum thickness.

Through the above steps, a polycrystalline Si thin film solar cell 11.1 is formed using the semiconductor device manufacturing method according to the above embodiment.

8. In the above example, a method was shown in which a microcrystalline film was formed on the insulating film and the entire exposed surface of the opening, but it is also possible to form the microcrystalline film only on the insulating film and the substrate in the opening. good. In addition, in the above embodiment, a method of recrystallizing all of the microcrystalline film on the insulating film may be selectively recrystallized. .

In addition, in the above embodiment, a case where it is used for manufacturing a polycrystalline Si thin film solar cell is shown, but an insulating film formed with a substrate and an opening selectively provided on the substrate, and an insulating film formed with an opening selectively provided on the substrate, The method of manufacturing a semiconductor device of this invention I can be used for any semiconductor device including a semiconductor layer formed on a film and a semiconductor layer formed on a substrate in an opening.

It is clear that active Si layers, such as for example three-dimensional integrated circuits, can be formed by the method according to the invention.

〔Effect of the invention〕

According to the present invention, a microcrystalline film is formed on the insulating film S formed on the substrate and on the substrate in the opening, and after selectively recrystallizing the microcrystalline film, half the Since a body layer is formed, a flat semiconductor layer with uniform properties in the direction parallel to the substrate is formed without loss of grain size. As a result, subsequent steps can proceed as intended, and semiconductor devices can be manufactured with good characteristics and less variation.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one embodiment of the manufacturing method of a semiconductor device according to the present invention in the order of steps. FIG. 2 is a schematic diagram schematically showing the basic structure of a solar cell, and FIG. 3 is a conventional semiconductor device. FIG. 3 is a cross-sectional view showing an example of a device manufacturing method in the order of steps. (2) is the semiconductor layer, (6) is the substrate, (7)
(8) is an insulating film, (8) is an opening, (3) is a microcrystalline film, and α4 is a recrystallized portion. 2. In the figures, the same symbols indicate the same or equivalent parts.

Claims (1)

[Claims] (1) A method for manufacturing a semiconductor device, comprising forming an insulating film having an opening selectively provided on a substrate, and forming a semiconductor layer on the insulating film and on the substrate in the opening, comprising: A method for manufacturing a semiconductor device, comprising: forming a microcrystalline film on the substrate above and in the opening; and selectively recrystallizing the microcrystalline film.