A gallium nitride substrate comprising a primary surface, the primary surface being tilted at an angle in a range of 20 to 160 degrees with respect to a C-plane of the substrate, and the substrate 5 having a fracture toughness of more than or equal to 1.36 MN/m3.

A gallium nitride substrate comprising a primary surface, the primary surface being tilted at an angle in a range of 20 to 160 20 degrees with respect to a C-plane of the substrate, the substrate having a fracture toughness of more than or equal to 1.36 MN/m32, the primary surface having a longitudinal direction and a transverse direction, the longitudinal direction being a [11-20] direction of the substrate, and the transverse direction being perpendicular to the [11-20] direction.

5 9.-A gallium nitride substrate comprising a primary surface, the primary surface being tilted at an angle in a range of 20 to 160 degrees with respect to a C-plane of the substrate, the substrate having a fracture toughness of more than or equal to 1.36 MN/m3/2, and an angle between the primary surface and the C-plane being in a range of 71 to 10 79 degrees.

A gallium nitride substrate comprising a primary surface 15 and a cleaved surface that extends in a direction perpendicular to the [11-20] direction, the primary surface being tilted at an angle in a range of 20 to 160 degrees with respect to a C-plane of the substrate, the substrate having a fracture toughness of more than or equal to 1.36 M N/m3/2

20 12. A gallium nitride substrate comprising a primary surface, the primary surface being tilted at an angle in a range of 20 to 160 degrees with respect to a C-plane of the substrate, and the substrate having a fracture toughness of more than or equal to 1.36 MN/m3/2, the primary surface having a longitudinal direction and a transverse 25 direction, the longitudinal direction being a [11-20] direction of the substrate, and the transverse direction being perpendicular to the [11-20] 15 FP 10-021 2-OO US-SE direction, an angle between the primary surface and the C-plane being in a range of 71 to 79 degrees.

A gallium nitride substrate comprising a primary surface, the primary surface being tilted at an angle in a range of 20 to 160 degrees with respect to a C-plane of the substrate, and the substrate 5 having a fracture toughness of more than or equal to 1.36 MN/m3.

A gallium nitride substrate comprising a primary surface, the primary surface being tilted at an angle in a range of 20 to 160 20 degrees with respect to a C-plane of the substrate, the substrate having a fracture toughness of more than or equal to 1.36 MN/m32, the primary surface having a longitudinal direction and a transverse direction, the longitudinal direction being a [11-20] direction of the substrate, and the transverse direction being perpendicular to the [11-20] direction.

5 9.-A gallium nitride substrate comprising a primary surface, the primary surface being tilted at an angle in a range of 20 to 160 degrees with respect to a C-plane of the substrate, the substrate having a fracture toughness of more than or equal to 1.36 MN/m3/2, and an angle between the primary surface and the C-plane being in a range of 71 to 10 79 degrees.

A gallium nitride substrate comprising a primary surface 15 and a cleaved surface that extends in a direction perpendicular to the [11-20] direction, the primary surface being tilted at an angle in a range of 20 to 160 degrees with respect to a C-plane of the substrate, the substrate having a fracture toughness of more than or equal to 1.36 M N/m3/2

20 12. A gallium nitride substrate comprising a primary surface, the primary surface being tilted at an angle in a range of 20 to 160 degrees with respect to a C-plane of the substrate, and the substrate having a fracture toughness of more than or equal to 1.36 MN/m3/2, the primary surface having a longitudinal direction and a transverse 25 direction, the longitudinal direction being a [11-20] direction of the substrate, and the transverse direction being perpendicular to the [11-20] 15 FP 10-021 2-OO US-SE direction, an angle between the primary surface and the C-plane being in a range of 71 to 79 degrees.

A gallium nitride substrate comprising a primary surface, the primary surface being tilted at an angle in a range of 20 to 160 degrees with respect to a C-plane of the substrate, and the substrate 5 having a fracture toughness of more than or equal to 1.36 MN/m3.

A gallium nitride substrate comprising a primary surface, the primary surface being tilted at an angle in a range of 20 to 160 20 degrees with respect to a C-plane of the substrate, the substrate having a fracture toughness of more than or equal to 1.36 MN/m32, the primary surface having a longitudinal direction and a transverse direction, the longitudinal direction being a [11-20] direction of the substrate, and the transverse direction being perpendicular to the [11-20] direction.

5 9.-A gallium nitride substrate comprising a primary surface, the primary surface being tilted at an angle in a range of 20 to 160 degrees with respect to a C-plane of the substrate, the substrate having a fracture toughness of more than or equal to 1.36 MN/m3/2, and an angle between the primary surface and the C-plane being in a range of 71 to 10 79 degrees.

A gallium nitride substrate comprising a primary surface 15 and a cleaved surface that extends in a direction perpendicular to the [11-20] direction, the primary surface being tilted at an angle in a range of 20 to 160 degrees with respect to a C-plane of the substrate, the substrate having a fracture toughness of more than or equal to 1.36 M N/m3/2

20 12. A gallium nitride substrate comprising a primary surface, the primary surface being tilted at an angle in a range of 20 to 160 degrees with respect to a C-plane of the substrate, and the substrate having a fracture toughness of more than or equal to 1.36 MN/m3/2, the primary surface having a longitudinal direction and a transverse 25 direction, the longitudinal direction being a [11-20] direction of the substrate, and the transverse direction being perpendicular to the [11-20] 15 FP 10-021 2-OO US-SE direction, an angle between the primary surface and the C-plane being in a range of 71 to 79 degrees.

A gallium nitride substrate comprising a primary surface, the primary surface being tilted at an angle in a range of 20 to 160 degrees with respect to a C-plane of the substrate, and the substrate 5 having a fracture toughness of more than or equal to 1.36 MN/m3.

A gallium nitride substrate comprising a primary surface, the primary surface being tilted at an angle in a range of 20 to 160 20 degrees with respect to a C-plane of the substrate, the substrate having a fracture toughness of more than or equal to 1.36 MN/m32, the primary surface having a longitudinal direction and a transverse direction, the longitudinal direction being a [11-20] direction of the substrate, and the transverse direction being perpendicular to the [11-20] direction.

5 9.-A gallium nitride substrate comprising a primary surface, the primary surface being tilted at an angle in a range of 20 to 160 degrees with respect to a C-plane of the substrate, the substrate having a fracture toughness of more than or equal to 1.36 MN/m3/2, and an angle between the primary surface and the C-plane being in a range of 71 to 10 79 degrees.

A gallium nitride substrate comprising a primary surface 15 and a cleaved surface that extends in a direction perpendicular to the [11-20] direction, the primary surface being tilted at an angle in a range of 20 to 160 degrees with respect to a C-plane of the substrate, the substrate having a fracture toughness of more than or equal to 1.36 M N/m3/2

20 12. A gallium nitride substrate comprising a primary surface, the primary surface being tilted at an angle in a range of 20 to 160 degrees with respect to a C-plane of the substrate, and the substrate having a fracture toughness of more than or equal to 1.36 MN/m3/2, the primary surface having a longitudinal direction and a transverse 25 direction, the longitudinal direction being a [11-20] direction of the substrate, and the transverse direction being perpendicular to the [11-20] 15 FP 10-021 2-OO US-SE direction, an angle between the primary surface and the C-plane being in a range of 71 to 79 degrees.