Patent ID: 7354477

Claim:
A method of growing a GaN crystal comprising the steps of: preparing an undersubstrate; forming a striped mask pattern made of a material inhibiting GaN from growing partially on the undersubstrate; forming parallel stripe-masked parts which are parts of the undersubstrate covered with mask stripes of the striped mask pattern and parallel non-masked parts which are parts of the undersubstrate not covered with the mask stripes; epitaxially growing the GaN crystal on the non-masked parts of the undersubstrate but not growing the GaN crystal on the stripe-masked parts of the undersubstrate at the beginning of GaN growth; forming a plurality of linearly extending parallel GaN facet hills having facets slantingly extending from edges of the stripe-masked parts to the non-masked parts; forming protrusions of GaN crystals which have reversed orientation different from that of the GaN crystal on the non-masked parts by 180 degrees and project slantingly from the slanting facets; extending the protrusions so as not to touch the mask stripes; unifying the protrusions near an upper middle of the stripe-masked parts; covering the whole stripe-masked parts with the protrusions; increasing a thickness of the GaN crystal on the non-masked parts with growing of the protrusions above the stripe-masked parts; increasing a thickness of the GaN crystal as a whole; and obtaining the GaN crystal having normal-oriented regions formed on the non-masked parts and the reverse-oriented regions formed on the stripe-masked parts.