GROUP III NITRIDE BULK CRYSTALS AND FABRICATION METHOD

摘要

Bulk crystal of group III nitride having thickness greater than 1 mm with improved crystal quality, reduced lattice bowing and/or reduced crack density and methods of making. Bulk crystal has a seed crystal, a first crystalline portion grown on the first side of the seed crystal and a second crystalline portion grown on the second side of the seed crystal. Either or both crystalline portions have an electron concentration and/or an oxygen concentration similar to the seed crystal.;The bulk crystal can have an additional seed crystal, with common faces (e.g. same polarity, same crystal plane) of seed crystals joined so that a first crystalline part grows on the first face of the first seed crystal and a second crystalline part grows on the first face of the second seed crystal. Each crystalline part's electron concentration and/or oxygen concentration may be similar to its corresponding seed crystal.

主权项

1. A bulk crystal of group III nitride having a composition of GaxAlyIn1-x-yN (0≦x≦1, 0≦x+y≦1) and a thickness greater than 1 millimeter wherein the bulk crystal has at least three portions,
(a) a first portion comprising a seed crystal having a first major face and a second major face, the first major face having an electron concentration, N1seed, the first major face having an oxygen concentration O1seed, the second major face having an electron concentration N2seed, and the second major face having an oxygen concentration O2seed; (b) a second portion on the first major face of the seed crystal and comprising a first crystalline region, wherein the first crystalline region has an electron concentration, N1st-xtal and an oxygen concentration O1st-xtal, (c) a third portion on the second major face of the seed crystal and comprising a second crystalline region, wherein said second crystalline region has an electron concentration N2nd-xtal, and an oxygen concentration O2nd-xtal, and (d) wherein the electron concentration and/or the oxygen concentration of the seed crystal, the first crystalline region, and the second crystalline region satisfy at least one of the following relationships:
0.1