JP2010267943A - Method of manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a semiconductor device intended to provide a high-efficiency thin-film polycrystalline silicon (Si) solar cell on glass. <P>SOLUTION: In this method of manufacturing the semiconductor device being a polycrystalline silicon (Si) solar cell, a large-particle-size polycrystalline silicon thin film is formed on a glass using a semiconductor-excited (diode-excited) solid-state continuous-wave laser; a PN junction is formed by forming a P-type region and an N-type region adjacently to each other in a region on the front surface side of the polycrystalline Si layer; a direction for connecting the P-type region to the N-type region is set generally parallel to a direction in which the crystal grain boundary of the polycrystalline Si runs; and a region where the Si layer does not exist partially is included. Thus, a translucent semiconductor device is formed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a semiconductor manufacturing method, and more particularly to a semiconductor manufacturing method for realizing a translucent high-efficiency thin-film polycrystalline silicon (Si) solar cell formed on glass.

  Recently, high-efficiency Si-based thin-film solar cells on glass have attracted attention. Current thin-film Si-based solar cells on glass are mainly thin-film Si-based materials made of amorphous or microcrystals.

  However, a thin film Si solar cell made of amorphous or microcrystal has a problem that conversion efficiency is low.

  Thin-film Si-based solar cells on glass, particularly thin-film Si-based solar cells made of amorphous or microcrystals, have a lower conversion efficiency than bulk single-crystal Si solar cells or bulk polycrystalline Si solar cells. This is because the crystal quality of amorphous Si or microcrystalline Si is inferior to that of single crystal Si or bulk polycrystalline Si.

  Therefore, if high-quality polycrystalline Si can be formed on glass, it is expected to bring about a great breakthrough in the conversion efficiency of thin-film Si-based solar cells on glass.

  The present invention has been made in view of the above problems, and in order to form a translucent high-efficiency thin-film polycrystalline Si solar cell on a glass substrate, it is a thin-film Si and has high conversion efficiency while being translucent. An object of the present invention is to provide a semiconductor manufacturing method for forming a polycrystalline Si thin film.

  As a result of intensive studies, the present inventor has conceived the following aspects of the invention.

  A large-grain polycrystalline Si thin film partially having Si is formed on glass using a semiconductor-excited (diode-excited) solid-state continuous wave laser, and in different regions on the surface of the polycrystalline Si film, and A PN junction is formed in the adjacent region. Furthermore, the direction of the PN junction has a structure that is substantially parallel to the crystal grain boundary.

  According to the present invention, it becomes possible to form translucent polycrystalline Si having a large particle diameter on glass, and from a thin-film Si-based solar cell made of amorphous Si or microcrystalline Si that is currently in practical use. It is possible to realize a highly efficient translucent thin-film polycrystalline Si solar cell on glass at a low cost.

  The present invention proposes a semiconductor manufacturing method for realizing a translucent thin-film polycrystalline Si solar cell having high conversion efficiency on a glass substrate at a low cost.

Hereinafter, specific embodiments of the present invention will be described in detail. In this embodiment, an example in which a large-grain polycrystalline Si thin film is formed using a wavelength of 532 nm, which is the second harmonic of Nd: YVO ₄ , as a solid-state continuous wave laser pumped by a semiconductor (diode pump) will be described in detail. .

  FIG. 1 is a schematic sectional view of a translucent thin-film polycrystalline Si solar cell formed on glass according to the present embodiment.

2 to 4 are schematic schematic diagrams showing a method for producing a translucent thin-film polycrystalline Si solar cell on glass in the order of steps.
First, as shown in FIG. 2A, an amorphous Si thin film 2 that is not doped with plasma CVD 1 or is slightly N-type or slightly P-type doped on a glass substrate 1 is grown to 1000 nm. . The amorphous Si thin film is formed by using silane gas.

  Subsequently, as shown in FIG. 2B, a region where the Si layer exists and a region where the Si layer does not exist are formed by dry etching. This makes it possible to form a translucent solar cell. The area of the region where Si is removed by dry etching is allowed to be designed as necessary.

Subsequently, as shown in FIG. 2C, a semiconductor-excited solid CW laser (Nd: YVO ₄ , wavelength 532 nm) having a wavelength of 532 nm is used, the power is set to 6.0 watts, and the laser scanning speed is 40 cm / s. The large grain polycrystalline Si layer 3 is formed by scanning with. The crystal grain size at this time is 3 μm × 20 μm.

Subsequently, as shown in FIG. 3A, a P region and an N region are formed in a region adjacent to the surface region of the polycrystalline Si semiconductor layer. Here, it was doped by ion implantation.
At this time, the direction from the adjacent P region to the N region is preferably substantially parallel to the direction of the crystal grain boundary of the large grain polycrystalline Si.

  Subsequently, as shown in FIG. 3B, the activation of the P region or the N region is performed using thermal activation or laser activation at a low temperature of about 550 ° C. to form the N + region and the P + region.

  For laser activation, activation using an excimer laser or activation using a solid laser is preferably performed.

  Finally, hydrogenation treatment is performed to terminate crystal grain boundaries and interface defects.

  The final form is shown in FIG. FIG. 4A is a schematic sectional view. FIG. 4B is a plan view. In this figure, the relationship between the crystal grain boundary, the N + region, and the P + region is shown.

  With this technique, a translucent high-efficiency thin-film polycrystalline Si solar cell can be formed on glass. The carriers generated by light irradiation reach the electrodes without recombination at the crystal grain boundaries because the carrier flow direction and the crystal grain boundary direction are substantially parallel. For this reason, it becomes possible to form a large grain thin film polycrystalline silicon solar cell having high conversion efficiency on glass.

It is the schematic which shows embodiment of this invention. It is the schematic which shows the semiconductor manufacturing method by embodiment of this invention in process order. FIG. 3 is a schematic view illustrating the semiconductor manufacturing method according to the embodiment of the present invention in the order of steps subsequent to FIG. 2. FIG. 4 is a schematic view illustrating the semiconductor manufacturing method according to the embodiment of the present invention in the order of steps subsequent to FIG. 3.

DESCRIPTION OF SYMBOLS 1 Glass substrate 2 Amorphous Si thin film 3 Large grain Si polycrystal thin film 4 by laser crystallization 4 N region 5 P region 6 Grain boundary

Claims (2)

A large-grain polycrystalline silicon (Si) thin film is formed on glass using a semiconductor-excited (diode-excited) solid-state continuous wave laser, and different regions on the surface side of the polycrystalline Si layer and adjacent regions PN junction, and the direction of the arrangement of the PN junction is substantially parallel to the direction of the grain boundary of the polycrystalline Si, and includes a region where the Si layer does not exist partially. And highly efficient semi-transparent thin-film polycrystalline Si solar cells. 2. A semiconductor-pumped (diode-pumped) solid-state continuous wave laser having a wavelength of 300 to 600 nm is used.

Images