JPS58167490A - Formation of single crystal on amorphous film - Google Patents

Abstract

PURPOSE:To form the titled single crystal by a simple process without causing thermal strain, by forming an amorphous film consisting of a same composition as a substrate bonded to the exposed area of the substrate, on an amorphous film consisting of a different compsn. formed on the substrate of a single crystal, irradiating the bonded area between the substrate and the amorphous film of the same compsn. with heavy ion beam. CONSTITUTION:For example, on the substrate 1 of a silicon single crystal is formed the amorphous film 2 of a different compsn. (e.g., oxidized film, nitrogen film, etc.) consisting of an atom (or melecule) different from the constituent atom (or molecule) of the substrate 1. On both the substrate 1 and the amorphous film 2 is formed the amorphous film 3 (e.g., amorphous silicon film) which is bonded through the window 2a of the amorphous film 2 to the substrate 1. The amorphous film 3 is irradiated with heavy ion beam 4 at a temperature <= the epitaxial temperature of solid phase in such a way that at least the bonded face between the amorphous film 3 and the substrate 1 is fully irradiated. The amorphous film can be recrystallized at low temperature of 200-300 deg.C, and the formation of the single crystal layer on the amorphous film can be carried out by a simplified process with preventing the occurrence of thermal strain and the redistribution of impurities.

Description

[Detailed description of the invention] The present invention relates to a method for forming a single crystal on an amorphous film.

Conventionally, as a method for forming a single crystal on an amorphous braid, for example, 808
There is a method of forming single crystal silicon on a sapphire substrate such as (Silic@n on 5aphir*). However, the ζO method has problems in that the lattice constants of the sapphire substrate and silicon do not completely match, and that gold is generated in the rounding, and that aluminum contamination occurs in the silicon. Also, SIMOX (8@paratl*m by
A method called "Implant@d Oxyg@n" has also been adopted in which a high concentration of implant is implanted into silicon to form an implanted oxide insulator, and then an epitaxial layer is further deposited. However, this method has the disadvantage that it requires a long time to form a single crystal due to the rounding of ion implantation of oxygen at an extremely high concentration. Then, CVD (Cksml@al Vap@r D@poai) was applied on the surface silicon oxide film.
A formation method has also been adopted in which amorphous silicon is deposited using a method such as tlon, and then crystallized by irradiation with an electron beam during radar.However, this method epitaxial growth temperature (~600°C for silicon) or liquid phase epitaxial growth temperature (
With silicon, crystal recovery is performed at temperatures above 1,400° C., which causes problems such as the occurrence of heat waves.

The present invention was made in view of such points, and 20
A monocrystalline film on an amorphous film that can crystallize an amorphous film at a low temperature of 0 to 300°C, and can form a single crystal layer on a non-solid material using a single simplified machine. A crystal formation method is provided.

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, for example, on a silicon single crystal substrate 1,
A heterogeneous amorphous film 2 made of atoms (or molecules) different from those of the substrate 1 is formed. For example, there is an oxide film or a nitride film as the J4 amorphous layer 1. Then, on the substrate 1 and the heterogeneous amorphous IIJ, a
A homogeneous amorphous BS is formed which is bonded to the substrate l through the window 21 of the BS. Homogeneous amorphous @J is an atom (or molecule) of substrate 1
Since 4 consists of the same atoms (or molecules) as 617. For example, when there is an amorphous silicon film, methods for forming homogeneous amorphous silicon include normal pressure CVD method, low pressure CVN method, and de9ye method.
MCVD method, MBIC method (Mol@@ular B@
Here, the heterogeneous amorphous film 1 and the homogeneous amorphous film S include polycrystalline films made of atoms or molecules that constitute them.

Next, the homogeneous amorphous film 1, the substrate 1, and the metal surface of the homogeneous amorphous film 1 are sufficiently irradiated with the heavy ion beam 4 at a temperature below the solid phase Evita critical temperature.
I shoot. The homogeneous amorphous layer SO is heated at a temperature below the solid phase epitaxial temperature of its constituent atoms or molecules.
If the temperature exceeds the solid phase epitaxial temperature, which is preferably set at 0° C. or higher, impurities in the homogeneous amorphous film 1 will be redistributed or hot gold will remain.

If the temperature does not reach 100" OK, homogeneous amorphous 1i1
1JKAs described below, it is not possible to sufficiently perform single crystallization, i9, heavy ion beam 0 irradiation energy is 0.3
MeV = 10 MeV O range WM It is desirable to set it appropriately e If O,3 MeV is not reached, homogeneous amorphous lI5 cannot be sufficiently single crystallized as described below e If it exceeds 10 MeV homogeneous amorphous IQ
A heavy ion beam penetrates between the lattices and single crystal grows in the same way.
It becomes difficult to apply

In this way, the heavy ion beam 4 is transferred to the homogeneous amorphous film 3.
When the irradiation is performed, a large number of vacancies and interstitial atoms are generated in the single crystal substrate 1 in contact with the homogeneous amorphous film S. Most of them recombine and form a single crystal substrate 1.
However, the vacancies and interstitial atoms formed near the interface with the homogeneous amorphous III form defects at the interface of the 5-substrate 1 before recombining.
It interacts with the homogeneous amorphous film J, and the homogeneous amorphous film S is epitaxially crystallized by the action IK. Then, the homogeneous amorphous film JK4 recrystallizes on the heterogeneous amorphous film 2,
In this way, a single crystal film fabrication on a heterogeneous amorphous l[J is formed.

When the irradiation dose of the high-energy heavy ion beam 4 is increased in this manner, the homogeneous amorphous film 3 crystallizes sequentially from the bonding interface with the single crystal substrate 1. *Figure 2 shows the homogeneous amorphous film S This figure shows the channel linda spectra obtained by crystallizing and using the backscattered liL method in Example 9. In Figure 8, l channel = 4・■
, the incident helium ion O energy is 1.54 M・
■It is. Also, in the same figure, l! 111ii11(4) is a well-aligned shaft immediately after the formation of the homogeneous amorphous film 3 (10G), and the homogeneous amorphous film 3 with a thickness of ~1500× is formed on the single crystal substrate 1. There is.Song-(B) is 2.56
The nine samples were irradiated with 5 X l 01S/J at a dose rate of 3.0, Q/4 ms'' and (1
00> well-axis spectrum), ~33 from the interface of substrate 1
A single crystal film with zero difference thickness is formed. Curve C is 2.5
6M・■ Mu I at a dose rate of 3.5 knots/412
For the sample irradiated with X 10 /cm (100>aligned axis spectrum a), a single crystal film with a thickness of ~730X is formed from the interface of the substrate 1.0 curve D Id, 2.56 M
eV OAl f 3.5 JAA7'4 ex2f)
The <100> aligned axis spectrum of the sample irradiated with 2 X l O''/32 with )"-slate matches the single crystal spectrum, and the homogeneous amorphous film 3 is completely crystallized. In this case, the crystallization is of the homogeneous amorphous film 3! ! Since this is done in the same manner in both the i direction and the horizontal direction, the homogeneous amorphous MAx on the heterogeneous amorphous film 2 is crystallized.

In addition, in the example shown in Figure 1 and (B) Fi, the heterogeneous amorphous pAx is an oxide film with a thickness of ~1000X,
On top of that, a homogeneous amorphous lI4 consisting of deposited silicon
The film thickness of 3 is ~4000X, and the lateral force direction of the densified film and each turn is O.
These are reflection electron beam diffraction images before (A in the same figure) and after (in the middle of the figure)) high-energy heavy ion beam annealing when the length was 10 mm. Here, (4) in the same figure is set at 600℃ in advance.
- This is a diffraction image of a sample in which a portion of a homogeneous amorphous film 3 of a single-crystal silicon substrate 1 is crystallized after being heat-treated in an electric furnace for 8 hours to form a hole. The same figure (g)) is
The sample was further exposed to 3.5 μA of 2.56 M@V As.
/ 4 m2 dose rate, I x 10”/ls2
This figure shows a diffraction image of a sample that was irradiated and annealed with a high-energy heavy ion beam. From FIG. 3B, it can be seen that the halo patterns characteristic of amorphous materials have disappeared, and crystallization has also spread over the oxide film.

In the example shown in Fig. 3 (4) and li2), the irradiation ion beam was Muhata and the irradiation energy was 2.56 M@V (D
＠Although VC is shown, the irradiated ion species are heavy principal ions with an atomic number exceeding 14.

Crystallization was possible using either sb or the like. It has been confirmed that the higher the atomic number, the faster the crystallization rate.
K H@ ' , B ''# As 'ζKr84 2.56M@Vte, 3. OJIA/ 4cv<2))
'-X Ray-) (substrate temperature ~ 290℃) 5
It shows the recrystallized thickness when irradiated with 0"/am'. It can be seen that the lighter H ions are hardly recrystallized, and the heavier the ions, the larger the recrystallized thickness.

Therefore, to reduce the temperature directly below the high-energy heavy ion beam spot, it is recommended to increase the scanning speed <(-10'c1n/a・C) and the beam diameter (~10+mφ).
The temperature could be lowered to below 0°C. Because the crystallization temperature is low, the impurity distribution in homogeneous amorphous aS is hardly affected by crystallization. lI example klKJt
This is clear from the experimental results shown in FIG. 10 in the figure is K 50 K in the homogeneous amorphous film S.
This is the distribution point of 5 x 1 o111/J injection system at low energy of @V. This is the glancing angle (glan@1
mg a! Igl*) 11 in the figure was measured using the backscattering method with improved resolution of approximately 35X.
It can be seen that the concentration distribution point of As after energy heavy ion beam annealing moves slightly from the interface toward the surface as K crystallizes epitaxially, but there is almost no change.

As explained above, according to the method for forming a single crystal on an amorphous film according to the present invention, the amorphous film can be recrystallized at a low temperature of 200°C to 300°C, so that thermal strain does not occur. This has remarkable effects such as preventing the redistribution of impurities and making it possible to form a single crystal layer on an amorphous film in a simplified process.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the state in which a homogeneous amorphous film on a heterogeneous amorphous film is single-crystalized by the method of the present invention, and FIG.
Figure 3) is a characteristic diagram showing the relationship between count number and channel number. Figure 3) is a diffraction photograph diagram showing the reflected electron beam diffraction image of a homogeneous amorphous film before heavy ion beam irradiation. A diffraction photograph showing the 0-grain electron beam diffraction image of the crystalline film after heavy ion beam irradiation, Figure 4 is an explanatory diagram showing the relationship between recrystallization thickness and mass number, and Figure 5 is the depth of the substrate. This is a characteristic diagram showing the distribution of the number of hits. 1...Substrate, 2...Heterogeneous amorphous film, 2d...Miya,
3... Homogeneous amorphous film, 4... Heavy ion beam, 1o
. . . As concentration distribution point, 11 . . . Mo concentration distribution point after heavy ion beam irradiation. Applicant's agent Patent attorney Suzue Takehiko Fang 3 figure (to) ■ Fang 4 figure (A/(C+ x 10')cm) Number of vl

Claims (1)

[Claims] # Forming a heterogeneous amorphous layer made of molecules or atoms different from the constituent molecules or atoms of the substrate so that a predetermined region of the substrate is exposed on the single crystal substrate, and then forming a homogeneous amorphous film on the heterogeneous amorphous film, which does not consist of the same molecules or atoms and is bonded to the exposed region of the substrate, and then solid phase epitaxial film of the molecules or atoms of the substrate; 4. Irradiating a heavy ion beam to at least the bonding surface of the substrate and the homogeneous amorphous film at a temperature equal to or lower than the above temperature.
111. Single crystal formation method on non-hexagonal glands.