摘要:
In the production of GaN through the flux method, deposition of miscellaneous crystals on the nitrogen-face of a GaN self-standing substrate and waste of raw materials are prevented. Four arrangements of crucibles and a GaN self-standing substrate are exemplified. In FIG. 1A, a nitrogen-face of a self-standing substrate comes into close contact with a sloped flat inner wall of a crucible. In FIG. 1B, a nitrogen-face of a self-standing substrate comes into close contact with a horizontally facing flat inner wall of a crucible, and the substrate is fixed by means of a jig. In FIG. 1C, a jig is provided on a flat bottom of a crucible, and two GaN self-standing substrates are fixed by means of the jig so that the nitrogen-faces of the substrates come into close contact with each other. In FIG. 1D, a jig is provided on a flat bottom of a crucible, and a GaN self-standing substrate is fixed on the jig so that the nitrogen-face of the substrate is covered with the jig. A flux mixture of molten gallium and sodium is charged into each crucible, and a GaN single crystal is grown on a gallium-face under pressurized nitrogen.
摘要:
An object of the invention is to carry out the flux method with improved work efficiency while maintaining the purity of flux at high level and saving flux material cost. The sodium-purifying apparatus includes a sodium-holding-and-management apparatus for maintaining purified sodium (Na) in a liquid state. Liquid sodium is supplied into a sodium-holding-and-management apparatus through a liquid-sodium supply piping maintained at 100° C. to 200° C. The sodium-holding-and-management apparatus further has an argon-gas-purifying apparatus for controlling the condition of argon (Ar) gas that fills the internal space thereof. Thus, by opening and closing a faucet at desired timing, purified liquid sodium (Na) supplied from the sodium-purifying apparatus can be introduced into a crucible as appropriate via the liquid-sodium supply piping, the sodium-holding-and-management apparatus, and the piping.
摘要:
Objects of the invention are to further enhance crystallinity and crystallinity uniformity of a semiconductor crystal produced through the flux method, and to effectively enhance the production yield of the semiconductor crystal. The c-axis of a seed crystal including a GaN single-crystal layer is aligned in a horizontal direction (y-axis direction), one a-axis of the seed crystal is aligned in the vertical direction, and one m-axis is aligned in the x-axis direction. Thus, three contact points at which a supporting tool contacts the seed crystal are present on m-plane. The supporting tool has two supporting members, which extend in the vertical direction. One supporting member has an end part, which is inclined at 30° with respect to the horizontal plane α. The reasons for supporting a seed crystal at m-plane thereof are that m-plane exhibits a crystal growth rate, which is lower than that of a-plane, and that desired crystal growth on c-plane is not inhibited. Actually, a plurality of seed crystals and supporting tools are periodically placed along the y-axis direction.
摘要:
Objects of the invention are to further enhance crystallinity and crystallinity uniformity of a semiconductor crystal produced through the flux method, and to effectively enhance the production yield of the semiconductor crystal. The c-axis of a seed crystal including a GaN single-crystal layer is aligned in a horizontal direction (y-axis direction), one a-axis of the seed crystal is aligned in the vertical direction, and one m-axis is aligned in the x-axis direction. Thus, three contact points at which a supporting tool contacts the seed crystal are present on m-plane. The supporting tool has two supporting members, which extend in the vertical direction. One supporting member has an end part, which is inclined at 30° with respect to the horizontal plane α. The reasons for supporting a seed crystal at m-plane thereof are that m-plane exhibits a crystal growth rate, which is lower than that of a-plane, and that desired crystal growth on c-plane is not inhibited. Actually, a plurality of seed crystals and supporting tools are periodically placed along the y-axis direction.
摘要:
An object of the invention is to carry out the flux method with improved work efficiency while maintaining the purity of flux at high level and saving flux material cost. The sodium-purifying apparatus includes a sodium-holding-and-management apparatus for maintaining purified sodium (Na) in a liquid state. Liquid sodium is supplied into a sodium-holding-and-management apparatus through a liquid-sodium supply piping maintained at 100° C. to 200° C. The sodium-holding-and-management apparatus further has an argon-gas-purifying apparatus for controlling the condition of argon (Ar) gas that fills the internal space thereof. Thus, by opening and closing a faucet at desired timing, purified liquid sodium (Na) supplied from the sodium-purifying apparatus can be introduced into a crucible as appropriate via the liquid-sodium supply piping, the sodium-holding-and-management apparatus, and the piping.
摘要:
An object of the present invention is to realize, by the flux process, the production of a high-quality n-type semiconductor crystal having high concentration of electrons. The method of the invention for producing an n-type Group III nitride-based compound semiconductor by the flux process, the method including preparing a melt by melting at least a Group III element by use of a flux; supplying a nitrogen-containing gas to the melt; and growing an n-type Group III nitride-based compound semiconductor crystal on a seed crystal from the melt. In the method, carbon and germanium are dissolved in the melt, and germanium is incorporated as a donor into the semiconductor crystal, to thereby produce an n-type semiconductor crystal.The mole percentage of germanium to gallium in the melt is 0.05 mol % to 0.5 mol %, and the mole percentage of carbon to sodium is 0.1 mol % to 3.0 mol %.
摘要:
An object of the present invention is to realize, by the flux process, the production of a high-quality n-type semiconductor crystal having high concentration of electrons. The method of the invention for producing an n-type Group III nitride-based compound semiconductor by the flux process, the method including preparing a melt by melting at least a Group III element by use of a flux; supplying a nitrogen-containing gas to the melt; and growing an n-type Group III nitride-based compound semiconductor crystal on a seed crystal from the melt. In the method, carbon and germanium are dissolved in the melt, and germanium is incorporated as a donor into the semiconductor crystal, to thereby produce an n-type semiconductor crystal.The mole percentage of germanium to gallium in the melt is 0.05 mol % to 0.5 mol %, and the mole percentage of carbon to sodium is 0.1 mol % to 3.0 mol %.
摘要:
An object of the present invention is to effectively add Ge in the production of GaN through the Na flux method. In a crucible, a seed crystal substrate is placed such that one end of the substrate remains on the support base, whereby the seed crystal substrate remains tilted with respect to the bottom surface of the crucible, and gallium solid and germanium solid are placed in the space between the seed crystal substrate and the bottom surface of the crucible. Then, sodium solid is placed on the seed crystal substrate. Through employment of this arrangement, when a GaN crystal is grown on the seed crystal substrate through the Na flux method, germanium is dissolved in molten gallium before formation of a sodium-germanium alloy. Thus, the GaN crystal can be effectively doped with Ge.
摘要:
It is provided a method of growing a single crystal by flux process from a melt containing sodium, in that a flux is contained in a reaction vessel made of yttrium-aluminum garnet. Compared with the case that an alumina or yttria vessel is used, it can be successfully obtained a single crystal whose incorporation amounts of oxygen and silicon can be considerably reduced, residual carrier density can be lowered, and electron mobility and specific resistance can be improved.
摘要:
An object of the present invention is to effectively add Ge in the production of GaN through the Na flux method. In a crucible, a seed crystal substrate is placed such that one end of the substrate remains on the support base, whereby the seed crystal substrate remains tilted with respect to the bottom surface of the crucible, and gallium solid and germanium solid are placed in the space between the seed crystal substrate and the bottom surface of the crucible. Then, sodium solid is placed on the seed crystal substrate. Through employment of this arrangement, when a GaN crystal is grown on the seed crystal substrate through the Na flux method, germanium is dissolved in molten gallium before formation of a sodium-germanium alloy. Thus, the GaN crystal can be effectively doped with Ge.