JPS60191090A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To convert surely and efficiently the insulator non-single crystal region into single crystals by forming plural insular non-single crystal regions in close proximity to one another on the surface of an insulating amorphous film, and irradiating an energy beam having Gaussian distribution of intensity to the boundary between adjacent insulator non-single crystal regions. CONSTITUTION:An amorphous insulating film 2 of SiO2, etc. is formed on a semiconductor substrate 1 of silicon, etc., and plural insulator non-single crystal regions 3 and 3 are formed in close proximity to one another and embedded into the surface of the amorphous insulating film 2. Then when an energy beam having Gaussian distribution of intensity is irradiated to the boundary between adjacent insular non-single crystal regions 3 and 3, the insular non-single crystal regions 3 and 3 are melted and recrystallized to grow crystal particles, and the insular single crystal layer is formed.

Description

[Detailed Description of the Invention] Technical Field> The present invention relates to a method for manufacturing a semiconductor device, and in particular to a method for manufacturing a semiconductor device, in particular a method for irradiating an energy beam onto a non-monocrystalline semiconductor layer such as a polycrystalline or amorphous semiconductor layer formed on an amorphous film surface. The present invention relates to a method of manufacturing a semiconductor device that is made into a single crystal by using a method of manufacturing a semiconductor device.

<Prior Art> In recent years, research has been conducted on converting non-single crystal thin films into single crystals and using them as semiconductor layers for three-dimensional stacked semiconductor devices and the like. This type of semiconductor layer is made by first forming an insulating amorphous thin film on a semiconductor substrate, forming a polycrystalline semiconductor layer on the amorphous insulating thin film, and then applying laser light, electron beam, etc. to the polycrystalline semiconductor layer. Recrystallization is performed by irradiation with an energy beam to grow crystal grains, preferably to form a single-crystal region, and the single-crystal semiconductor region is used as a semiconductor layer for forming devices.

In this process, a polycrystalline semiconductor layer is irradiated with an energy beam to melt and recrystallize it.

In order to make a polycrystalline semiconductor layer into a single crystal consisting of one crystal grain, it is extremely difficult to make it into a single crystal by simply melting it with an energy beam and then solidifying it, so conventional methods have been developed to control crystal growth. is proposed. One method is to form a polycrystalline semiconductor layer into an island shape and then irradiate it with laser light. According to this method,
If the island-shaped polycrystalline fractures are sufficiently small compared to the beam diameter, the polycrystalline layer will be completely melted by the laser beam irradiation, and when this region solidifies, the molten state will become the nucleus for crystal growth. There are no crystals. Furthermore, since the island shape is sufficiently small, the substrate around the island absorbs the laser beam and is heated, and due to heat conduction from the substrate, the temperature becomes higher than that at the center of the polycrystalline region. For this reason, a crystal grows from the center of the island in a low temperature state by single nucleation, and the entire island is recrystallized into a single crystal.

Single crystallization as described above is possible only when the size of the island region is sufficiently small compared to the diameter of the energy beam, and if the island region becomes large, single crystallization is difficult for the following reasons.

In other words, normal laser light emitted from a light source exhibits an intensity distribution, and when such a beam is irradiated, the energy intensity irradiated to the center of the island is the strongest, resulting in high temperature, and therefore the above-mentioned It is difficult to reverse a temperature distribution where the temperature at the center is lower than the surrounding area, and the temperature at the center of the island is often higher than the surrounding area due to the influence of reflectance due to variations in the thickness of the insulating film on the base. crystal growth occurs from several surrounding locations, resulting in the formation of polycrystals.

The above temperature distribution also tends to occur when the substrate supporting the polycrystalline layer absorbs the laser beam and it is difficult to heat the surrounding area of the island region by heat conduction. is difficult.

<Objective of the Invention> The present invention provides a method for reliably and efficiently monocrystallizing an island-shaped non-single crystal layer by irradiating an energy beam by eliminating the drawbacks of the conventional semiconductor device manufacturing method described above.

<Example> In FIG. 1, a semiconductor substrate such as silicon
An amorphous insulating film 2 such as 02 is formed, and a non-single crystal region 3 such as polycrystalline or amorphous is embedded in the surface of the amorphous insulating film 2.
, 3... are formed in an island shape. The non-single crystal regions 3, 3
. . . is buried in the insulating film 2 as on the Kinomio side,
It may be formed simply by laminating on the insulation@2.

The non-single crystal regions 3, 3, . . . are semiconductor regions that are melted by energy from a laser beam and grown into a single crystal in the process of recrystallization. As shown in FIG. 2, the spacing 2a between adjacent regions is set so that the center 4a of the laser beam 4 having a Gaussian distribution is irradiated between the island regions. Adjacent non-single crystal region 3
, amorphous insulation 1 located in the gap between 3! ! With the intensity peak located at 2a, laser light 4 having a Gaussian distribution is irradiated onto the non-single crystal regions on both adjacent sides and scanned as shown in FIG. In the non-single crystal region irradiated with the laser beam, the temperature at the center of the beam becomes higher than the outside, and as the beam scans, the melted island region begins to solidify from the outer edges A and B where the temperature is lower. That is, the nucleus generation location during single crystallization is constant, crystal growth progresses from the above-mentioned grains A and B, and the entire island region is uniformly single crystallized.
In one scan, the non-single crystal regions on both sides are recrystallized.

In the above recrystallization process, the amorphous insulating film 2 serving as the base
It is not affected by the film thickness of the semiconductor substrate 1 or the type of the semiconductor substrate 1, and the temperature on the center side of the beam in the island region is always higher than the outside, the position of the nucleus generation is stabilized, and the generated nucleus is used as a seed. crystals grow.

Key words are crystallized.

Effects> As described above, according to the present invention, a crystalline semiconductor layer for an island-like part can be reliably converted into a high-quality single-crystalline semiconductor layer by recrystallization, and a semiconductor for a three-dimensional stacked semiconductor device, etc. Layers can be easily created.

[Brief explanation of the drawing]

FIG. 1 is a structural diagram of a semiconductor substrate for explaining one embodiment of the present invention, FIG. 2 is a diagram showing the positional relationship between the laser light intensity distribution and the substrate for explaining the embodiment, and FIG. 3 is a diagram for explaining the same embodiment. It is a figure which shows the scanning of the laser beam and the nucleus generation position by the same Example. 1: Semiconductor substrate, 2: Amorphous insulating film, 3: Non-single crystal island region

Claims (1)

[Claims] 1) Form a plurality of island-shaped non-single crystal regions adjacent to each other on the surface of the insulating amorphous film, and at the boundary between the adjacent island-shaped non-single crystal regions,
1. A method for manufacturing a semiconductor device, which comprises irradiating an energy beam with an intensity distribution to recrystallize a non-single crystal region to grow crystal grains.