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AssigneesAmmono Sp. Z.O.O., Nichia Corporation
InventorsRobert Dwilinski, Roman Doradzinski, Jerzy Garczynski, Leszek Sierputowski, Yasuo Kanbara
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The invention relates to new improvements in a process for crystal growth in the environment of supercritical ammonia-containing solution, which are based on use of specific azide mineralizers and result in the improved bulk Group XIII element nitride monocrystals, in particular balk monocrystalline gallium-containing nitride, intended mainly for variety of nitride-based semiconductor products such as various opto-electronic devices. The invention further relates to a mineralizer used for supercritical ammonia-containing solution which comprises at least one compound selected from the group consisting of LiN3, NaN3, KN3, and CsN3.
Process for obtaining bulk gallium-containing nitride monocrystals from supercritical ammonia-containing solution in the presence of a mineralizer, characterized in that in a pressurized reaction vessel—using ammonia as solvent and Group I element azides and optionally Group II element azides as mineralizer, a supercritical ammonia-containing solution including Group I and optionally Group II element ions is first obtained to dissolve next a gallium-containing feedstock at dissolution temperature and/or dissolution pressure and then the desired gallium-containing nitride is crystallized from the supercritical solution on the surface of at least one seed at the crystallization temperature and/or crystallization pressure, wherein the crystallization temperature and/or crystallization pressure is selected according to the temperature coefficient of solubility and pressure coefficient of solubility of the desired gallium-containing nitride to be crystallized.
Process for obtaining bulk gallium-containing nitride monocrystals from supercritical ammonia-containing solution in the presence of Group I and optionally Group II element-containing mineralizer, characterized in that when gallium-containing nitride has a negative temperature coefficient of solubility and a positive pressure coefficient of solubility in supercritical ammonia-containing solution, in the presence of Group I and optionally Group II element-containing mineralizer, in a pressurized reaction vessel—using Group I element azides and optionally Group II element azides as mineralizers—supercritical ammonia-containing solution including Group I and optionally Group II element ions is first obtained to dissolve next a gallium-containing feedstock at dissolution temperature and/or dissolution pressure and then gallium-containing nitride is crystallized from the supercritical solution on the surface of at least one seed by means of bringing the temperature to crystallization temperature and/or the pressure to crystallization pressure, the crystallization temperature being higher than the dissolution temperature and/or the crystallization pressure being lower than the dissolution pressure at least at the crystallization zone of the pressurized reaction vessel, where the seed is placed—so that super-saturation of the supercritical solution with respect to the seed is achieved—and then the super-saturation of the supercritical solution is maintained at the level at which spontaneous crystallization of the nitride may be neglected, while crystallization of the desired gallium-containing nitride is carried out on the seed.
Mineralizer used for supercritical ammonia-containing solution which comprises at least one compound selected from the group consisting of LiN3, NaN3, KN3, and CsN3.
Dependencies are inferred from the claim text.