JPH04285096A - Method for growing si-ge single crystal - Google Patents

Abstract

PURPOSE:To grow an Si-Ge single crystal contg. >=30% Ge by the Czochralski method. CONSTITUTION:When an Si-Ge single crystal 9 is grown by the Czochralski method, the ratio between Si and Ge at the growth interface 10 is calculated from the X-ray absorption coefft. with an X-ray generator 2 and an X-ray TV camera 3. The concn. of Ge in the single crystal 9 is controlled by regulating the amt. of cylindrical polycrystalline Ge 8 melted. By this method, an Si-Ge single crystal contg. >=30% Ge can be grown.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for growing Si--Ge single crystals using the Czochralski method.

0002

BACKGROUND OF THE INVENTION Single crystal growth using the Czochralski method allows the growth of large diameter single crystals, and many single crystals are grown using this method. However, when growing Si-Ge single crystals using the Czochralski method, the liquidus and solidus lines in the phase diagram of Si-Ge are wide apart, so the composition ratio fluctuates greatly in the crystal growth direction, resulting in a single crystal. It is difficult to obtain crystals. For this reason, when growing a Si-Ge single crystal using the Czochralski method, only a single crystal with a Ge concentration of 30% or less can be obtained.

0003

[Problems to be Solved by the Invention] In the conventional Si-Ge single crystal growth method using the Czochralski method, the composition of the crystal growth interface cannot be measured. For this reason, it was difficult to control the composition in the crystal growth direction, and a single crystal with a Ge concentration of 30% or more could not be obtained.

[0004] The object of the present invention is to reduce the Ge concentration in the crystal to 3.
An object of the present invention is to provide a single crystal growth method for obtaining a Si-Ge single crystal of 0% or more.

[0005]

[Means for Solving the Problems] In order to achieve the above object, in the Si-Ge single crystal growth method according to the present invention, S
A crystal growth method that grows i-Ge single crystals using the Czochralski method, in which the concentration of Ge in the single crystal at the crystal growth interface is detected using X-ray fluoroscopy, and the detection results are fed back to the raw material supply source. This method controls the Ge concentration in the single crystal to grow a Si--Ge single crystal with a Ge composition ratio of 30% or more.

[0007]

[Operation] According to the present invention, by using X-ray fluoroscopy, fluctuations in the composition ratio at the crystal growth interface can be detected by changes in the absorption coefficient of X-rays, and the amount of raw material supplied can be controlled to achieve any desired composition. A Si-Ge single crystal can be grown. For this reason,
A single crystal with a Ge concentration of 30% or more can be grown.

[0008]

[Embodiments] Hereinafter, embodiments of the present invention will be explained with reference to the drawings. FIG. 1 is a configuration diagram showing an apparatus for carrying out the crystal growth method according to the present invention. In the figure, the apparatus according to the present invention includes a Czochralski method single crystal growth furnace main body 1 that performs crystal growth,
An X-ray generator 2, an X-ray TV camera 3 for observing a fluoroscopic image of X-rays, a monitor television 4 for projecting a fluoroscopic image, and an image processing device 5 for measuring an X-ray absorption coefficient from an X-ray fluoroscopic image. It is composed of a computer 6, a raw material supply amount control device 7, and a rod-shaped Ge polycrystal 8 for supplying raw materials.

As an example, by this method, a melt containing 10% Ge was first prepared using a Si single crystal as a seed crystal, and
A case will be described in which a single crystal with a maximum Ge concentration of 40% is grown. That is, S by the Czochralski method
In the i-Ge single crystal growth method, the composition ratio at the growth interface 10 is determined from the X-ray absorption coefficient by X-ray fluoroscopy using the X-ray generator 2 and the X-ray TV camera 3. Then, by adjusting the amount of rod-shaped polycrystalline Ge8 dissolved, the Ge concentration in the single crystal is controlled. By this method, S containing 30% or more of Ge
i-Ge single crystals can be grown.

FIG. 2 is a diagram showing the relationship between an X-ray fluoroscopic image of a crystal growth state and an X-ray absorption coefficient at a growth interface during crystal growth. This figure shows that the X-ray absorption coefficients of the Si--Ge single crystal 9, the growth interface 10, and the Si--Ge melt 11 are different. In (a), when the crystal has grown to a certain extent, the X-ray absorption coefficient becomes large at the growth interface, indicating that the Ge concentration is high. (b) shows when the crystal has grown to the straight body, and the Ge concentration increases at the growth interface, but the Ge concentration in the melt decreases. Immediately after this, polycrystalline G
e8 was dissolved to increase the Ge concentration in the melt. (c)
indicates the change in Ge concentration at that time.

[0011] The single crystal thus grown contained 5% to 40% Ge, as determined by measurement of lattice constants using the bond method and mass spectrometry using SIMS.

As described above, crystal growth with controlled Ge composition has become possible, and Si-Ge containing 30% or more of Ge can be grown.
It was confirmed that single crystals could be grown.

[0013]

Effects of the Invention The present invention makes it possible to grow Si-Ge single crystals containing arbitrary Ge compositions, and allows Si-Ge single crystals containing 30% or more Ge, which could not be obtained by conventional methods, to grow.
It has become possible to grow i-Ge single crystals by the Czochralski method.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing a crystal growth apparatus used in the present invention.

FIGS. 2A, 2B, and 2C are diagrams showing the relationship between X-ray fluoroscopic images of crystal growth states and X-ray absorption coefficients for explaining examples.

[Explanation of symbols]

1　Crystal growth furnace main body 2. X-ray generator 3. X-ray TV camera 4 Monitor TV 5 Image processing device 6 Computer 7 Raw material supply amount 8 Rod-shaped polycrystalline Ge 9 Si-Ge single crystal 10 Growth interface 11 Si-Ge melt

Claims (1)

[Claims] [Claim 1] A crystal growth method in which a Si-Ge single crystal is grown by the Czochralski method, in which the concentration of Ge in the single crystal at the crystal growth interface is detected by X-ray fluoroscopy, and the detection results are recorded. The Ge concentration in the single crystal is controlled by feeding back to the raw material supply source, and Si-
A Si-Ge single crystal growth method characterized by growing a Ge single crystal.