JPS62297296A - Vapor phase epitaxy process - Google Patents

Abstract

PURPOSE:The crystal-growing base plate is allowed to rotate in the reaction tube to effect the crystal growth as the base is reciprocated in the cross direction to the gas flow whereby the characteristics on the center of the rotation in the growth layer is brought close to those in the other parts. CONSTITUTION:A GaAs base plate 3 as a crystal-growing plate is placed on the susceptor in the horizontal quartz reaction tube 1. The susceptor 2 is allowed to rotate through the shaft 4 by an external driving force whereby the base plate 3 is allowed to rotate around its center. Further, bellows 6 is reciprocated so that the susceptor 2 is reciprocated through the shaft 5 in the cross direction to the gas flow. The power is applied to the induction heating coil 9 to heat the base plate up to about 650 deg.C and a mixture of H2+TMG+AsH4+SiH4 is introduced from the inlet 7 using H2 from the inlet 8 as a carrier gas where the epitaxial growth of GaAs is effected on the base plate 8.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Summary] In order to make the growth layer uniform, growth is usually performed while rotating the growth substrate, but in this case, the carrier concentration of the growth layer is reduced at the center of rotation. It gets expensive. To this end, we propose a growth method in which the growth substrate is rotated and simultaneously moved back and forth in a direction that intersects the flow direction of the source gas, thereby making the carrier concentration distribution of the growth layer uniform.

[Industrial application field]

The present invention relates to a vapor phase growth method that improves the uniformity of carrier concentration in a growth layer of a compound semiconductor or the like.

Vapor phase growth methods, such as metal organic chemical vapor deposition (MOCV)
Method D) uses organic metal as a raw material gas, introduces it into a reaction tube, and thermally decomposes it on the growth target substrate to perform epitaxial growth.

[Conventional technology]

FIG. 4 is a plan view illustrating an MOCVD apparatus that implements the conventional method.

In the figure, a QaAs substrate is placed on a susceptor 2 in a horizontal reaction tube 1 as a growth substrate 3.

The susceptor 2 is rotated from outside the reaction tube 1 via the rotation transmission shaft 4 so that the growth substrate 'ui3 can rotate around its center.

Power is applied to the induction heating coil 9 to heat the substrate to be grown, a raw material gas containing an organometallic gas is introduced from the gas lower 4, and a recarrier gas is introduced from the other gas inlet 8 to form a compound semiconductor. Grow the layers epitaxially.

FIG. 5 is a distribution diagram of the carrier concentration within the growth substrate when the growth is performed by applying rotation.

In the figure, the horizontal axis is the distance from the center of the growth substrate, and the vertical axis is the carrier concentration.

As shown in the figure, a singular point is formed near the center (rotation center) of the growth substrate, and the carrier concentration is high.

[Problem that the invention seeks to solve]

When a substrate to be grown is rotated in a conventional MOCVD reaction tube, the epitaxially grown layer is very uniform, but there is a drawback that the carrier concentration is higher near the center of rotation than in other parts.

[Means for solving problems]

The above-mentioned problems can be solved by a vapor phase growth method in which growth is performed while rotating the growth substrate in a reaction tube and making it reciprocate in a direction intersecting the flow direction of the raw material gas.

To achieve this, a bellows is used to apply reciprocating motion to the susceptor from outside the reaction tube.

[Operation] When epitaxial growth is performed by rotating the growth substrate, the center of rotation is always at the same position and other parts are moving, so the center of rotation of the growth layer has different characteristics from other parts. It becomes like this.

As a countermeasure to this, the characteristics of the rotation center of the growth layer are brought closer to those of other parts by moving the rotation center itself.

〔Example〕

FIG. 1 is a plan view illustrating an MOCVD apparatus implementing the present invention.

In the figure, a GaAs substrate is placed as a growth substrate 3 on a susceptor 2 in a horizontal reaction tube 1 made of quartz.

The susceptor 2 is rotated from outside the reaction tube 1 via the rotation transmission shaft 4 so that the growth substrate 3 can rotate around its center.

Further, the bellows 6 is given a reciprocating motion, and the susceptor 2 is caused to reciprocate with an amplitude of about 2 cm across the flow of the raw material gas via the support shaft 5 attached to the bellows 6.

Applying power to the induction heating coil 9, the substrate to be grown is heated 65
Heating to 0℃, using TMG (trimethyl gallium) as the organic metal, H2 + TMG + A from the gas introduction lower
stl) 10 SiH4 is introduced, and only H2 is introduced as a carrier gas from the other gas inlet 8 to form GaAs.
was grown epitaxially.

FIG. 2 is a side sectional view illustrating the structure of the susceptor used in the example.

In the figure, a susceptor 2 made of carbon includes a susceptor rotating part 2A and a susceptor fixing part 2B.

Rotation of the susceptor rotating section 2A on which the growth substrate 3 is placed is transmitted via a rotation transmission shaft 4 made of carbon by bevel gears cut on each contact surface.

The support shaft 5 is fixed to the susceptor fixing part 2B and reciprocates in a direction perpendicular to the plane of the paper.

The rotation of the susceptor in this case is 10 rpm, and the reciprocating motion is 10 times/min with an amplitude of 8 mm.

In this embodiment, the carrier concentration distribution of the growth substrate 3 is uniform as shown in FIG.

FIG. 3 is a carrier concentration distribution diagram within the growth substrate when growth is performed by applying rotation and reciprocating motion.

In the figure, the horizontal axis is the distance from the center of the growth substrate, and the vertical axis is the carrier concentration.

As shown in the figure, there is no singular point near the center of the growth substrate, and the carrier concentration is uniform over the entire surface of the substrate.

Although the MOCVD method has been described in the embodiment, the effects of the present invention are similar to other vapor phase growth methods.

〔Effect of the invention〕

As explained above, according to the present invention, the rotation center of the growth base slope does not remain at the same position, so that the carrier concentration at the rotation center can be brought closer to other parts, allowing uniform growth within the substrate.

[Brief explanation of the drawing]

FIG. 1 is a plan view illustrating an MOCVD apparatus embodying the present invention, and FIG. 2 is a side sectional view illustrating the structure of a susceptor used in an example. Fig. 3 is a carrier concentration distribution diagram in the growth substrate when growth is performed by applying rotation and reciprocating motion, Fig. 4 is a plan view illustrating an MOCVD apparatus that implements the conventional method, and Fig. 5 is a diagram showing the distribution of carrier concentration within the growth substrate when the growth is performed by applying rotation and reciprocating motion. FIG. 3 is a distribution diagram of carrier concentration within a growth target substrate during growth. In the figure, 1 is a reaction tube, 2 is a susceptor, 3 is a growth substrate, 4 is a rotation transmission shaft, 5 is a support shaft,
6 is bellows, 7.8 is gas thick inlet, 9
Is the induction heating coil thick August Saitoba Jro 1 Rice CVD installation's side Ro No. 1 Ko board medium 1 Deer ＼ et al distance (insect enemy) Roo anti! Wang Yixia 1 Motion Begging 1 The distribution map 2
3 KO1 Example 1 [Used +f CE]・7 side attack cave Fig. 2

Claims (1)

[Claims] A vapor phase growth method characterized by performing growth while rotating a substrate to be grown in a reaction tube and making it reciprocate in a direction crossing the flow direction of a source gas.