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US 10,947,638 B2Granted
Underlying substrate including a seed crystal layer of a group 13 nitride having stripe-shaped projections and recesses and an off-angle in a direction of an a-axis
AssigneeNGK Insulators, Ltd.
InventorsTakayuki Hirao, Makoto Iwai, Katsuhiro Imai, Takashi Yoshino
Life of this patent
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Abstract
An underlying substrate including a seed crystal layer of a group 13 nitride, wherein projections and recesses repeatedly appear in stripe shapes at a principal surface of the seed crystal layer, and the projections have a level difference of 0.3 to 40 μm and a width of 5 to 100 μm, and the recesses have a bottom thickness of 2 μm or more and a width of 50 to 500 μm.
Claims5
An underlying substrate including a seed crystal layer of a group 13 nitride,
- wherein projections and recesses repeatedly appear in stripe shapes at a principal surface of the seed crystal layer,
- the projections have a level difference of 0.5 to 10 μm and a width of 10 to 50 μm, and the recesses have a bottom thickness of 2 μm or more and a width of 100 to 250 μm,
- an off-angle formed by a normal line of the principal surface of the seed crystal layer and a c-axis of the seed crystal layer is 0.36 to 1.2° in an a-axis direction of the group 13 nitride, and
- surfaces of the projections are not masked and the group 13 nitride is exposed.
1 more element
Dependencies are inferred from the claim text.