JPS6384013A - Manufacture of semiconductor crystal layer - Google Patents

Abstract

PURPOSE:To form a semiconductor crystal layer having no crystal defect by covering the top of a semiconductor layer which becomes the semiconductor crystal layer with a high melting point metallic oxide film, and then melting and recrystallizing the semiconductor layer. CONSTITUTION:A silicon oxide film 12 is formed by a CVD method on a single crystal silicon substrate 11, and a polycrystalline silicon layer 13 is formed by a CVD method using a thermal decomposition of silane on the upper surface. Then, a ZrO2 layer 14, for example, is formed as a high melting point metallic oxide layer by a sputtering method thereon. A sample 10 formed in this manner is scanned with an energy beam 15, such as a scanning type electron beam 15 in a direction of an arrow in the figure, the layer 13 is sequentially melted, and recrystallized to form a single crystal silicon layer 13a. Thus, a silicon crystal layer having less crystal defect and high quality can be formed.

Description

[Detailed Description of the Invention] 1''-i7 [Object of the Invention] ?i Recently, technology has been developed to form the So1 layer by an annealing method using energy beam irradiation such as an electron beam or a laser beam, a zone melt method using a strip heater, etc. is being actively developed.

The goal of this Sol technology is to fabricate a high-speed operating device by forming an integrated circuit two-dimensionally on SOI, or to fabricate a three-dimensional integrated device by forming an integrated circuit in multiple layers.

The 801 layer is usually formed by forming the 8102 layer as an insulating layer on a silicon single crystal substrate, depositing a polycrystalline silicon layer on top of it, depositing 3102M as a protective film on top of it, and then following the steps described above. A method is used in which the polycrystalline silicon layer is made into a single crystal by melting and recrystallizing the polycrystalline silicon layer by energy beam annealing or zone melting. However, in this case, the silicon layer after recrystallization does not become a complete single crystal layer, but has -
--As a method to improve this, a method as shown in FIG. 4 has been used.

That is, an insulating layer (42) having an opening (41) is formed on a silicon substrate (40), and then a polycrystalline or amorphous silicon layer is formed on the insulating layer (42) and the opening (41).
After depositing a protective 8102 layer (44) on the entire surface, an energy beam (45) such as an electron beam or a laser beam is irradiated in the direction of the arrow from B in the figure,
By melting and recrystallizing the single crystal silicon, epitaxial growth progresses in the vertical direction and then in the horizontal direction, giving crystal orientation information of the silicon substrate (40) to the single crystal layer growing on the insulating RF;A (42). be able to.

However, the distance from the opening (41) to the single crystal layer in the same orientation as the silicon substrate (40) is at most 100μ.
The growth is only about m, and in regions beyond this distance, problems such as subgrain boundaries and grain boundaries occur even with this method.

The fundamental cause of these conventional methods is that when the polycrystalline or amorphous silicon layer (4B) is a molten silicon layer (47) as shown in FIG.
Part of the two layers (42) and (44) dissolves, increasing the oxygen concentration in the molten silicon layer (47) and exceeding the solid solution limit concentration in silicon, resulting in the formation of precipitates during recrystallization. However, this is thought to lead to the generation of grain boundaries. This consideration shows that the solid solubility limit of oxygen in solid silicon just below the melting point is 1.5 to 3X10''cm-3, and the protective 5102 layer shown in Figure 5 in the normal Sol recrystallized layer (
44) The method of drilling a part of the hole is Prolf're
r et al., Appl, Phys.

Lett, 47 (1985057,
This method utilizes the phenomenon of evaporation from the opening in the form of 0). According to this method, the oxygen concentration in the Sol recrystallized layer can be reduced, thereby making it possible to form an S01 layer with fewer crystal defects.

However, with this method, the protective film is not continuous.The present invention was made in view of the above-mentioned conventional problems.The purpose of the present invention is to reduce the oxygen concentration in Sol during the recrystallization process, and to achieve flatness with few crystal defects. The objective is to form a high quality 801 layer with excellent properties.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides a method for forming a semiconductor crystal layer on a semiconductor substrate on which an insulating layer is deposited. A method for manufacturing a semiconductor crystal layer is provided, which comprises depositing a high-melting point metal oxide film on the top of the semiconductor layer, and then melting and recrystallizing the previous two semiconductor layers to form a semiconductor crystal layer.

(Function) The principle of the present invention is that by using a material highly permeable to oxygen atoms and silicon oxide molecules, that is, a high melting point metal oxide film, as the 801 surface protective film, Sol can be regenerated using an electron beam, for example. There is also a method of depositing a silicon layer or a metal layer on the protective film for the purpose of outward diffusion of excess oxygen in Sol during the crystallization process, that is, evaporation from the surface, and removing the oxygen concentration of the Sol recrystallized layer. It is valid.

(Example) Hereinafter, an example according to the present invention will be described using the drawings. FIG. 1 is a process sectional view showing a first embodiment of the present invention. The sample (lO) used here is first shown in Figure 1(a).
As shown in Figure 2, silicon oxidation (St
02) A film (12) was deposited, and the thickness was
A 0.6 μm polycrystalline silicon layer (13) is deposited on top of it by sputtering to form a high melting point layer, which contains less oxygen than the target material film composition and becomes Zr02-x. , polycrystalline silicon layer (13)
are sequentially melted and recrystallized to form a single crystal silicon layer (13a).
was formed to have 801 layers.

The scanning of the electron beam (15) is T, 1lao+asak
l et al.

J. Appl. Phys. 59 (198B) 2971.
l: The following method was used.

That is, a spot beam with a half-width of about 150 μm is deflected in one direction at high speed using a 36 MHz amplitude-modulated sine wave, and a pseudo-linear beam with a length of about 5 m11 is used. A modulated wave with a computer-controlled waveform was used to equalize the longitudinal intensity distribution of the linearized beam at Hz.

This linearized beam (15) is heated to a beam acceleration voltage of 12
kV, beam current 9.5mAs scanning speed 100mm/s
When the crystalline silicon layer (13) is melted and recrystallized, there are many crystal grain boundaries parallel to the scanning direction with an average interval of 10 μm, but in the above example, the average interval is 200 μm.
As a result, the area of the uniform single crystal region increased dramatically.

At this time, the Z"02 layer (14) and the single crystal silicon layer (13)
At the interface a), Zr5IOi! l:;Z r O2+
A reaction of SI Q 2 occurs, and an extremely thin 810
It is thought that two layers are formed and the oxygen concentration gradient increases from this interface toward the surface of the Z'02 layer.

Next, a second embodiment of the present invention will be described using FIG. 2.

As in the example, the scanning electron beam (15) is scanned to melt and recrystallize the polycrystalline silicon layer.
One layer can be formed. Components that are the same as those in FIG. 1 are denoted by the same reference numerals, and the method of forming them is the same as in the first embodiment, so detailed explanation will be omitted.

In the resulting 801 layer, fewer grain boundaries were generated than in the first example. In other words, the interval between grain boundaries is 2 to 3 mm, and there are some regions with an interval of ~5 mm. Obtaining such a large-area single crystal layer is also effective in subsequently forming semiconductor elements on this single crystal layer.

This result shows that during the recrystallization process, the above-mentioned excess oxygen diffuses into the Zr02 layer (14) and reacts with the silicon atoms of the polycrystalline silicon Il?IC1B) deposited on this Zr02 layer. The 5102 layer is formed, and the oxygen concentration in the 501 layer is much lower than the solid solubility limit of oxygen in silicon. 5I02 with a thickness of 2.0am
A film (12) is deposited, and a portion with a width of 2.0 μm that should be a seed portion is removed by normal photoetching to form an opening (
17). Then C using pyrolysis of SiH4
The opening part (17) and the 5102 membrane (12
) A polycrystalline silicon layer (13) with a thickness of 0.6 μm is deposited continuously over the entire surface, and a ZrO2 layer (14) and a polycrystalline silicon layer (13) are deposited on top of it in exactly the same manner as in the second embodiment.
6) were deposited sequentially. As shown in FIG. 3(b), a polycrystalline silicon layer (13) is formed on this sample by scanning electron beam annealing (15) from A' in the direction of the arrow in the same manner as in the first embodiment. A single crystal silicon layer (13a) was used. The resulting layer 801 is epitaxially grown in the lateral direction through the seed portion, so that it is a single crystal with the same orientation as the silicon of the substrate (11). In this example, almost no grain boundaries were observed, and the region surrounded by the seeds in the 5-square pattern formed a complete single crystal layer with no grain boundaries. The material of the oxygen absorption layer provided in the layer is not necessarily a polycrystalline silicon layer (16), but may be amorphous silicon, germanium, or GaAs.

A semiconductor layer such as Ga, P, etc., or a semiconductor layer such as Sn, T1. Hf.

Nb, Fe, Cu, In, sb, Ni, Pd.

It may also be a metal layer such as 1st grade.

In addition, in the first to third embodiments described above, a zirconium oxide layer was used as the surface protective layer of SOl, but hafnium oxide, titanium oxide, and mixtures of yttrium oxide and silicon oxide were also used. A similar effect can be obtained by using other materials.

Although sputtering was used to form these surface protective layers, the same effect could be obtained by forming them by vacuum evaporation, CVD, etc., and by using zone melting (ZMR), which uses tar or lamp heating, etc. can get.

[Effect of the invention] As described above, according to the present invention, the conventional 501
The occurrence of crystal defects caused by excessive precipitation of oxygen in the layer can be significantly reduced.

[Brief explanation of the drawing]

1 to 3 are cross-sectional views showing embodiments of the present invention,
FIGS. 4 and 5 are explanatory diagrams for explaining a conventional example. 11...Substrate, 12...Oxide film, 13...Polycrystalline silicon film, 13a...Single crystal silicon layer, 14...
- High melting point metal oxide layer, 15... Energy beam, 16... Polycrystalline silicon layer. Applicant: Director of the Agency of Industrial Science and Technology Kozo Iizuka Figure 1 Figure 2 Figure 3 Figure I Figure 4

Claims (6)

[Claims] (1) In a method of forming a semiconductor crystal layer on a semiconductor substrate on which an insulating layer is deposited, a high melting point metal oxide film is deposited on the top of the semiconductor layer to be used as the semiconductor crystal layer, and then the semiconductor layer is 1. A method for producing a semiconductor crystal layer, which comprises melting and recrystallizing to form a semiconductor crystal layer. (2) The semiconductor crystal layer according to claim 1, wherein a zirconium-based oxide, a hafnium-based oxide, a titanium-based oxide, or a mixture thereof is used as the high-melting point metal oxide. Production method. (3) The method for manufacturing a semiconductor crystal layer according to claim 1, wherein at least one of a semiconductor layer and a metal layer is deposited on the high melting point metal oxide layer. (4) The semiconductor crystal layer according to claim 1, wherein the recrystallization of the semiconductor layer is performed through an opening provided in the insulating layer by scanning an energy beam. Production method. (5) The method for manufacturing a semiconductor crystal layer according to claim 1, wherein the semiconductor crystal layer is a semiconductor single crystal layer. (6) The method for manufacturing a semiconductor crystal layer according to claim 1, wherein the semiconductor layer to be the semiconductor crystal layer is a polycrystalline or amorphous semiconductor layer.