A method for forming a photon absorbing layer. A substrate having a target surface is introduced into a controllable environment, and the pressure within the controllable environment is reduced. A first flux of a semiconductor material and a second flux of a dopant are simultaneously directed toward the target surface for a period of time, thereby producing a thickness of a substantially amorphous layer of the semiconductor material and dopant on the target surface. The semiconductor layer is laser annealed to convert it to a substantially multi-crystalline layer.

A large Group III nitride crystal of high quality with few defects such as a distortion, a dislocation, and warping is produced by vapor phase epitaxy. A method for producing a Group III nitride crystal includes: a first Group III nitride crystal production process of producing a first Group III nitride crystal 1003 by liquid phase epitaxy; and a second Group III nitride crystal production process of producing a second Group III nitride crystal 1004 on the first crystal 1003 by vapor phase epitaxy. In the first Group III nitride crystal production process, the surfaces of seed crystals 1003a (preliminarily provided Group III nitride) are brought into contact with an alkali metal melt, a Group III element and nitrogen are cause to react with each other in a nitrogen-containing atmosphere in the alkali metal melt, and the Group III nitride crystals are bound together by growth of the Group III nitride crystals grown from the seed crystals 1003a to produce a first crystal 1003.

There is provided a method for manufacturing a nitride crystal substrate, including: arranging a plurality of seed crystal substrates made of a nitride crystal in a planar appearance, so that their main surfaces are parallel to each other and their lateral surfaces are in contact with each other; growing a first crystal film using a vapor-phase growth method on a surface of the plurality of seed crystal substrates arranged in the planar appearance, and preparing a combined substrate formed by combining the adjacent seed crystal substrates each other by the first crystal film; growing a second crystal film using a liquid-phase growth method on a main surface of the combined substrate so as to be embedded in a groove that exists at a combined part of the seed crystal substrates, and preparing a substrate for crystal growth having a smoothened main surface; and growing a third crystal film using the vapor-phase growth method, on the smoothed main surface of the substrate for crystal growth.

A large Group III nitride crystal of high quality with few defects such as a distortion, a dislocation, and warping is produced by vapor phase epitaxy. A method for producing a Group III nitride crystal includes: a first Group III nitride crystal production process of producing a first Group III nitride crystal 1003 by liquid phase epitaxy; and a second Group III nitride crystal production process of producing a second Group III nitride crystal 1004 on the first crystal 1003 by vapor phase epitaxy by causing a Group III element metal to react with an oxidizing agent and nitrogen-containing gas. In the first Group III nitride crystal production process, the surfaces of seed crystals 1003a (preliminarily provided Group III nitride) are brought into contact with an alkali metal melt, a Group III element and nitrogen are cause to react with each other in a nitrogen-containing atmosphere in the alkali metal melt, and the Group III nitride crystals are bound together by growth of the Group III nitride crystals grown from the seed crystals 1003a to produce a first crystal 1003.

This disclosure provides a method and a device for manufacturing a semiconductor substrate. The method for manufacturing a semiconductor substrate comprises the following steps: heating a semiconductor material to a molten state to obtain a molten semiconductor material; thermally spraying the molten semiconductor material onto a baseplate by using a thermal spraying gun, then cooling to solidify the molten semiconductor material on the baseplate to obtain the semiconductor substrate. The disclosed method offers, when manufacturing the semiconductor substrate, high material utilization, low manufacturing cost, and the ability to manufacture larger semiconductor substrate, with controllable thickness and high purity, providing broad application prospects.

A semiconductor wafer comprising single-crystal silicon has defined concentrations of oxygen, nitrogen and hydrogen; the semiconductor wafer further comprises: BMD seeds having a density averaged over the radius of not less than 110.sup.5 cm.sup.3 and not more than 110.sup.7 cm.sup.3; surface defects having a density averaged over the radius of not less than 1100 cm.sup.2; and BMDs, whose density is not lower than a lower limit of 510.sup.8/cm.sup.3. The semiconductor wafers are produced by a process which enables obtention of the required ranges of concentrations of oxygen, nitrogen, hydrogen, BMD seeds, and BMD's.

A free-standing substrate of a polycrystalline nitride of a group 13 element contains a plurality of monocrystalline particles having a particular crystal orientation in approximately a normal direction. The polycrystalline nitride of the group 13 element is composed of gallium nitride, aluminum nitride, indium nitride or a mixed crystal thereof. The free-standing substrate has a top surface and bottom surface. The free-standing substrate contains at least one of zinc and calcium. A root mean square roughness Rms at the top surface is 3.0 nm or less.

A free-standing substrate of a polycrystalline nitride of a group 13 element is composed of a plurality of monocrystalline particles having a particular crystal orientations in approximately a normal direction. The free-standing substrate has a top surface and a bottom surface. The polycrystalline nitride of the group 13 element is gallium nitride, aluminum nitride, indium nitride or a mixed crystal thereof and contains zinc at a concentration of 110.sup.17 atoms/cm.sup.3 or more and 110.sup.20 atoms/cm.sup.3 or less.

Provided is a method for producing a SiC single crystal which can suppress generation of SiC polycrystals. The method according to the present embodiment is in accordance with a solution growth method. The method for producing a SiC single crystal according to the present embodiment comprises a power-output increasing step, a contact step, and a growth step. In the power-output increasing step, high-frequency power output of an induction heating device is increased to crystal-growth high-frequency power output. In the contact step, a SiC seed crystal is brought into contact with a SiC solution. The high-frequency power output of the induction heating device in the contact step is more than 80% of the crystal-growth high-frequency power output. The temperature of the SiC solution in the contact step is less than a crystal growth temperature. In the growth step, the SiC single crystal is grown at the crystal growth temperature.

In a first step, protrusions (42) are formed on a surface of an SiC substrate (40), and the SiC substrate (40) is etched. In a second step, the protrusions (42) of the SiC substrate (40) are epitaxially grown through MSE process, and an epitaxial layer (43a) containing threading screw dislocation, which has been largely grown in the vertical (c-axis) direction as a result of MSE process, is at least partially removed. In a third step, MSE process is performed again on the SiC substrate (40) after the second step, to cause epitaxial layers (43) containing no threading screw dislocation to be grown in the horizontal (a-axis) direction to be connected at the molecular level, so that one monocrystalline 4HSiC semiconductor wafer (45) having a large area is generated throughout an Si-face or a C-face of the SiC substrate (40).