Method for the growth of silicon carbide single crystals

• US 5,279,701 A
• Filed: 08/24/1992
• Issued: 01/18/1994
• Est. Priority Date: 05/11/1988
• Status: Expired due to Fees

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Suzuki, Akira, Shigeta, Mitsuhiro, Fujii, Yoshihisa, Furukawa, Katsuki
• Primary Examiner(s): Straub, Gary P.
• Application Number:
  US07/933,964
• Time in Patent Office: 512 Days
• Field of Search: 156/610, 156/611, 156/612, 156/613, 156/614, 156/DIG. 64, 148/DIG. 648, 437/93
• US Class Current: 117/101
• CPC Class Codes: C30B 25/02 Epitaxial-layer growth
• CPC Class Codes: C30B 25/18 characterised by the substrate
• CPC Class Codes: C30B 29/36 Carbides
• CPC Class Codes: Y10S 148/148 Silicon carbide
• CPC Class Codes: Y10S 438/931 Silicon carbide semiconductor
• CPC Class Codes: Y10S 438/973 Substrate orientation

Abstract

A method for the growth of silicon carbide single crystals is disclosed which includes the step of growing silicon carbide single crystals on a silicon single-crystal substrate. The silicon single-crystal substrate has growth areas with a crystal orientation inclined by an angle θ from the [100] direction toward at least one of the [011] and [011] directions and with a lateral dimension d taken along the direction of such inclination toward the [011] or [011] direction. The angle θ is set to be in the range of zero to tan^-1 (√2/8) degrees (with the proviso that the angle θ is not equal to tan^-1 (√2/2) degrees). The lateral dimension d is set to be in the range of 0.1 to 100 μm. In this method, the silicon carbide single crystals are grown to a thickness t approximately equal to or greater than (√2+tanθ)d/|1-√2tanθ|, so that these silicon carbide single crystals are substantially free of defects such as stacking faults.

Claims

1. A method for the growth of silicon carbide single crystals, said method comprising the preparation of a silicon single crystal substrate having growth areas and the step of growing silicon carbide single crystals on the growth areas with a thickness approximately equal to a more than critical thickness t,

said growth areas having a crystal orientation inclined by an off angle θ

from the [100] direction toward the [011] or [011] direction and said off angle θ

being smaller than 10°

(ten degrees) (with the proviso that the angle θ

is not equal to tan (√

2/2) degrees),

said critical thickness t being approximately equal to d(√

2+tanθ

)/|1-√

2tanθ

| for said off angle θ and

a lateral dimension d,

said lateral dimension d being specified by rectangular coordinates attached onto said growth area,

the two axes of said rectangular coordinates being taken parallel and perpendicular to [011] in case of an off angle θ

toward [011],

or the two axes of said rectangular coordinates being taken parallel and perpendicular to [011] in case of an off angle θ

toward [011],

said lateral dimension d being equal to the length of said growth area along said axis perpendicular to [011] in case of an off angle θ

toward [011],

or said lateral dimension d being equal to the length of said growth area along said axis perpendicular to [011] in case of an off angle θ

toward [011], and

said lateral dimension d being in the range of 0.1 to 100 μ

m.

2. A method for the growth of silicon carbide single crystals according to claim 1,

wherein said off angle θ

is equal to tan^-1 (√

2/n) from the [100] direction toward the [011] direction,

said critical thickness t being approximately equal to √

2d(n+1)/|n-2| (where n is an integer of from 1 to 8, with proviso that it is not equal to

     2).

8. A method for the growth of silicon carbide single crystals according to claim 2, wherein n is equal to 6.

3. A method for the growth of silicon carbide single crystals, said method comprising the preparation of a silicon single crystal substrate having growth areas and the step of growing silicon carbide single crystals on the growth areas with a thickness approximately equal to or more than a critical thickness t,

said growth areas having a crystal orientation of [100], said critical thickness t being approximately equal to √

2d for a lateral dimension d,

said lateral dimension d being specified by rectangular coordinates attached onto said growth area,

the two axes of said rectangular coordinates being taken parallel to [011] and [011],

said lateral dimension d being equal to the longer one of the length of said growth area along said axes, and

said lateral dimension d being in the range of 0.1 to 100 μ

m.

4. A method for the growth of silicon carbide single crystals, said method comprising the preparation of a silicon single crystal substrate having growth areas and the step of growing silicon carbide single crystals on the growth areas with a thickness approximately equal to or more than a critical thickness t,

said growth areas having a crystal orientation inclined by an off angle θ

from the [100] direction toward the [011] or [011] direction and said off angle θ

being smaller than 10°

(ten degrees) (with the proviso that the angle θ

is not equal to tan (√

2/2) degrees),

said critical thickness t being approximately equal to d(√

2+tanθ

)/|1-√

2tanθ

| for said off angle θ and

a lateral dimension d,

said lateral dimension d being specified by rectangular coordinates attached onto said growth area,

the two axes of said rectangular coordinates being taken parallel and perpendicular to [011] in case of an off angle θ

toward [011],

or the two axes of said rectangular coordinates being taken parallel and perpendicular to [011] in case of an off angle θ

toward [011],

said lateral dimension d being equal to the length of said silicon carbide single crystal grown on said growth area along said axes perpendicular to [011] in case of an off angle θ

toward [011],

or said lateral dimension d being equal to the length of said silicon carbide single crystal grown on said growth area along said axis perpendicular to [011] in case of an off angle θ

toward [011], and

said lateral dimension d being in the range of 0.1 to 100 μ

m.

6. A method for the growth of silicon carbide single crystals according to claim 4,

wherein said off angle θ

is equal to tan^-1 (√

2/n) from the [100] direction toward the [011] direction,

said critical thickness t being approximately equal to √

2d(n+1)/|n-2| (where n is an integer of from 1 to 8, with proviso that it is not equal to

     2).

7. A method for the growth of silicon carbide single crystals according to claim 6, wherein n is equal to 6.

5. A method for the growth of silicon carbide single crystals, said method comprising the preparation of a silicon single crystal substrate having growth areas and the step of growing silicon carbide single crystals on the growth areas with a thickness approximately equal to or more than a critical thickness t,

said growth areas having a crystal orientation of [100], said critical thickness t being approximately equal to √

2d for a lateral dimension d,

said lateral dimension d being specified by rectangular coordinates attached onto said growth area,

the two axes of said rectangular coordinates being taken parallel to [011] and [011],

said lateral dimension d being equal to the longer one of the length of said silicon carbide single crystal grown on said growth area along said axes, and

said lateral dimension d being in the range of 0.1 to 100 μ

m.