Semiconductor base material and method of manufacturing the material

• US 20040048471A1
• Filed: 04/17/2003
• Published: 03/11/2004
• Est. Priority Date: 09/18/2000
• Status: Active Grant

• Current Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Original Assignee: Mitsubishi Cable Industries Limited (Mitsubishi Materials Corporation)
• Inventors: Ouchi, Yoichiro, Tsunekawa, Takashi, Tadatomo, Kazuyuki, Okagawa, Hiroaki
• Granted Patent: US 7,179,667 B2
• Time in Patent Office: Days
• US Class Current: 438/689
• CPC Class Codes: C30B 25/18 characterised by the substrate
• CPC Class Codes: C30B 29/403 AIII-nitrides
• CPC Class Codes: H01L 21/0237 Materials
• CPC Class Codes: H01L 21/0242 Crystalline insulating materials
• CPC Class Codes: H01L 21/02433 Crystal orientation
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 21/02639 Preparation of substrate for selective deposition
• CPC Class Codes: H01L 21/02642 Mask materials other than SiO2 or SiN
• CPC Class Codes: H01L 21/0265 Pendeoepitaxy

Abstract

As shown in FIG. 1(a), substrate 1 having a growth plane having a concavo-convex surface is used. When GaN group crystal is vapor phase grown using this substrate, the concavo-convex shape suppresses growth in the lateral direction and promotes growth in the C axis direction, thereby affording a base surface capable of forming a facet plane. Thus, as shown in FIG. 1(b), a crystal having a facet plane is grown in a convex part, and a crystal is also grown in a concave part. When the crystal growth is continued, the films grown from the convex part and the concave part are joined in time to cover a concavo-convex surface and become flat as shown in FIG. 1(c). In this case, an area having a low a dislocation density is formed in the upper part of the convex part where facet plane was formed, and the prepared film has high quality.

Claims

1. A semiconductor base comprising a substrate and a semiconductor crystal grown by vapor phase growth on the substrate, wherein said substrate has a crystal growth plane having a concavo-convex surface and said semiconductor crystal has been grown from the concave part and/or the convex part while forming a facet structure.

2. The semiconductor base of claim 1, wherein said semiconductor crystal is InGaAlN.

3. The semiconductor base of claim 1, wherein said semiconductor crystal is AlGaN.

4. The semiconductor base of claim 1, wherein the crystal growth plane of said substrate comprises convex parts forming a parallel stripe pattern.

5. The semiconductor base of claim 4, wherein said semiconductor crystal is InGaAlN and the longitudinal direction of the stripe is parallel to the (1-100) plane or the (11-20) plane of the InGaAlN crystal.

6. The semiconductor base of claim 5, wherein the longitudinal direction of the stripe concavo-convex processed on said substrate is parallel to the (1-100) plane or the (11-20) plane of said InGaAlN crystal and the precision thereof is within 10.

7. The semiconductor base of claim 6, wherein the convex part concavo-convex processed on said substrate has a width A, the concave part adjacent thereto has a width B, the total thereof (A+B) is not more than 20 μ

m, and a depth h of said concave part is not less than 20% of the greater width of A or B.

8. The semiconductor base of claim 1, wherein an angle formed by a rising slope of the convex part concavo-convex processed on said substrate, and a substrate plane is not smaller than 60°

.

9. The semiconductor base of claim 1, wherein the convex part concavo-convex processed on said substrate has a curved bottom surface.

10. The semiconductor base of claim 1, wherein the concave plane of the concavo-convex surface of the substrate is processed such that a crystal growth does not occur substantially from the surface thereof, and said semiconductor crystal has been grown from the convex part while forming a facet structure.

11. The semiconductor base of claim 1, wherein said substrate is a crystal substrate comprising sapphire (C-plane, A-plane, R-plane), SiC (6H, 4H, 3C), GaN, AlN, Si, Spinel, ZnO, GaAs or NGO, or a substrate wherein a GaN semiconductor has been epitaxially grown on said crystal substrate.