JPS6292429A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent cracks and crystal defects from being generated in the process of recrystallization, by exposing both sides of side walls on grooves formed in a silicon wafer to make single crystal silicon grow on the single crystal. CONSTITUTION:A number of parallel groove 12 partitioned by side walls 13 are formed in a silicon wafer 11. A silicon nitriding film 14 and an SiO2 film 15, which are sued as masks during formation of the grooves, are left as they are, and a nitriding film 16 is made to grow all over the surface, and then the nitriding film 16 is left on only sides walls 13 on the grooves. And, the bottom surface of the groves are oxidized to form an insulating film 17, whose thickness T has a relation W/2<=T with width W of the side wall on the grooves. Then, the nitriding film 16, SiO2 film 15, and nitriding film 14 are removed and a single crystal silicon 18 is made to grow all over the surface so that a desirable isolation layer 19 is formed to make element-formation region 20. Hence, single crystal silicon, in which cracks and crystal defects are prevented from invading the insulating film, can be formed.

Description

[Detailed Description of the Invention] [Summary] A silicon-on-silicon method that forms single crystal silicon on an insulating film.
Insulator (Silicon on In5ula)
tor+SOI) technology.

[Industrial Application Field] The present invention relates to a method for manufacturing a semiconductor device. More specifically, the present invention relates to a method for manufacturing a semiconductor device. More specifically, a selective epitaxial growth technique is used to grow a single crystal on an insulating film by epitaxial growth (epitaxial growth) from the sidewall. It's about technology.

[Conventional technology]

Oxide film [silicon dioxide (S'r0
2) Form a film], grow polycrystalline silicon (polysilicon) on it, melt the polysilicon by laser annealing, and recrystallize it to form single crystal silicon on 5iO2N.It is called 501. The technology is known.

[Problem that the invention seeks to solve]

In the above-mentioned technique, cranks and crystal defects may occur in single crystal silicon after recrystallization, and it is extremely difficult to form single crystal silicon on an insulating film.

The present invention was created in view of these points, and relates to a technique for forming single crystal silicon without cracks or crystal defects on an insulating film.

[Means for solving problems]

FIGS. 1 ial to Ig+ are cross-sectional views of an embodiment of the present invention in the process of carrying out the method of the present invention, and FIG. 2 is a plan view of the embodiment.

In the embodiment of the present invention, a side wall 1 is attached to a silicon wafer 11.
A silicon nitride film (S) was used as a mask in forming the grooves.
i3N, lI'll, hereinafter referred to as nitride film) 14 and 5i0
2 film 15 is left as it is, nitride film 111i16 is grown on the entire surface, the nitride film 16 is left only on the side wall 13 of the trench, and the bottom surface of the trench is oxidized so that the thickness '' is W// with respect to the width W of the side wall of the trench. 2<
An insulating film 17 having a relationship of T is formed, and then a nitride film 16 is formed.
．． 5i02 15, nitride film 14 is removed, single crystal silicon is grown on the entire surface for 1 day, and a desired isolation layer (
Isolation 11)+9 is formed to form an element formation region 20.

[Effect]

In the above method, the grooves and sidewalls formed by JF in the silicon wafer are used, and both sides of the sidewalls are exposed and single crystal silicon is grown on the single crystal, so there is no need for annealing as in conventional SOI technology. This prevents the occurrence of cracks and crystal defects in the conventional recrystallization process.゛[Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

See FIG. 1(a): A nitride film 14, SiO2 on a semiconductor substrate, for example, a wafer 11.
The film 15 is formed into a film shape 5, and these films are patterned to form a groove 12 between the side walls 13 using the nitride film 14 and the SiO+ film 15 as a mask, as shown in FIG. The process described above is accomplished by forming a plurality of parallel grooves 12 in wafer 11, as partially shown in the plan view of FIG.

The width of the groove is set to 5 to 30 μm, the depth H is set to about 2 μm, and the width W of the side wall is set to about 1.0 μm. In the embodiment of the present invention, the width D° of the groove is set to 6 μm. 1 (see BL) Next, a nitride film 16 is grown on the entire surface to a thickness of 2000 nm.

FIG. 1 (see C1: Next, the nitride film on the top of the sidewall and the bottom of the groove 12 is removed by anisotropic etching. With anisotropic etching, the nitride film on the flat surface is etched uniformly. Even after the nitride 11ii16 on the bottom of the trench is removed and the wafer is exposed, nitride II!16 remains on both sides of the sidewall 13.

FIG. 1 (see dl: Next, the wafer surface with the exposed bottom is oxidized by thermal oxidation to form the SIO+ insulating film 17. At this time, since the entire surface of the side wall 13 is covered with a nitride film, Although not oxidized, the thickness T of the thickest central portion of the insulating film is equal to the width W of the sidewall so that the S'i 0'2 film is continuous as shown in the figure at the base of the sidewall (so that no cuts occur). Against W/
Oxidize to satisfy the condition 2<T.

Refer to FIG. 1, tel: Next, the nitride film 16 on the sidewalls is removed using phosphoric acid boiling, and then the 5i02 film 15 and nitride film 14 are removed to expose the sidewalls 13.

FIG. 1 (see fl: Next, selective shrimp growth is performed using SiHα3 gas at a temperature of 900°C to 1000°C in a vacuum of several tens of Torr. In the embodiment of the present invention, the width of the groove is 5 μm, and single crystal silicon is grown on the side wall 13 to a thickness of 4.8 to 5.5 μm. Not only was it completely filled with crystalline silicon, but the single-crystal silicon surface was also made almost flat.If the single-crystal silicon surface has some unevenness, it can be solved by melting only the surface with laser annealing or by dry etching after melting. Alternatively, it can be polished and flattened, followed by a controlled etching process to the desired thickness.

Refer to FIG. 1fgl: Then, a desired isolation [19] is formed by, for example, selective oxidation (LOGO3) to form an element formation region 20 surrounded by an insulating film.

〔Effect of the invention〕

As described above, according to the present invention, SOI technology can be realized in devices by forming single crystal silicon on an insulating film, and single crystal silicon can be formed with better reproducibility than beam annealing method. The method of the present invention includes:
It can be widely applied to CMO3, bipolar devices, etc.

[Brief explanation of drawings]

Figure 1 (al or gl is a sectional view of an embodiment of the present invention,
The figure is a plan view of an embodiment of the present invention. In Figures 1 and 2, 11 is a wafer, 12 is a groove, 13 is a side wall, 14 is a nitride film, 15 is a SiO2 film, 16 is a nitride film, 17 is a 5i02 film, 18 is single crystal silicon, and 19 is an isolator. ration 1-1 l (8) 20 is an element formation region. 4ζ departure! Ilf misery [Kita l sand ☆ 11-5mu P2A; 噌く, @ep+＠ りyl ip+qhrfB 2nd figure $ wo wo wo I] Damen ヱ 1st figure

Claims (2)

[Claims] (1) Using the film obtained by patterning the silicon nitride film (14) and insulating film (15) formed on the semiconductor substrate (11) as a mask, the semiconductor substrate (11) is separated by the sidewall (13). A step of forming a groove (12), a step of growing a silicon nitride film (16) on the entire surface of the substrate (11), a step of anisotropic etching to leave the nitride film (16) on the sidewalls (13) but forming the groove. etching the substrate (11) to expose the bottom surface of the substrate (11); and oxidizing the exposed surface of the substrate (11) to expose the substrate (11).
) Step of forming an insulating film (17) on the surface, side wall (13)
Step of removing the silicon nitride film (16) remaining on both sides of the single crystal silicon by selective epitaxial growth.
) is also grown in the lateral direction to fill the groove (13) with single crystal silicon. (2) Oxidize the substrate (11) to satisfy the following condition: W/2<T, where W is the width of the side wall (13) and T is the thickness of the thickest part of the insulating film (17). A method according to claim 1, characterized in that: