The present invention relates to silicon carbide (SiC) devices having a surface that has been activated to enhance properties including strength, porosity, and bioactivity. Activation may include forming silica gel with or without silicon nitride on the surface. The invention further relates to methods of making the devices and using the devices.

A nitride semiconductor device includes a substrate; a nitride semiconductor multilayer structure which is formed on the substrate, includes a first nitride semiconductor layer and a second nitride semiconductor layer having a different composition from that of the first nitride semiconductor layer, and generates two dimensional electron gas on a hetero interface between the first nitride semiconductor layer and the second nitride semiconductor layer; and an insulating film which covers at least a portion of a surface of the nitride semiconductor multilayer structure, has a concentration of SiH bonds equal to or less than 6.010.sup.21 cm.sup.3, and is formed of silicon nitride.

A method of manufacturing a plurality of through-holes in a layer of first material by subjecting part of the layer of said first material to ion beam milling.

For batch-wise production, the method comprises after a step of providing the layer of first material and before the step of ion beam milling, providing a second layer of a second material on the layer of first material, providing the second layer of the second material with a plurality of holes, the holes being provided at central locations of pits in the first layer, and subjecting the second layer of the second material to said step of ion beam milling at an angle using said second layer of the second material as a shadow mask.

Described herein are precursors and methods for forming silicon-containing films. In one aspect, there is provided a precursor of Formula I:

##STR00001##

wherein R.sup.1 is selected from linear or branched C.sub.3 to C.sub.10 alkyl group, linear or branched C.sub.3 to C.sub.10 alkenyl group, linear or branched C.sub.3 to C.sub.10 alkynyl group, C.sub.1 to C.sub.6 dialkylamino group, electron withdrawing group, and C.sub.6 to C.sub.10 aryl group; R.sup.2 is selected from hydrogen, linear or branched C.sub.1 to C.sub.10 alkyl group, linear or branched C.sub.3 to C.sub.6 alkenyl group, linear or branched C.sub.3 to C.sub.6 alkynyl group, C.sub.1 to C.sub.6 dialkylamino group, C.sub.6 to C.sub.10 aryl group, linear or branched C.sub.1 to C.sub.6 fluorinated alkyl group, electron withdrawing group, and C.sub.4 to C.sub.10 aryl group; optionally wherein R.sup.1 and R.sup.2 are linked together to form ring selected from substituted or unsubstituted aromatic ring or substituted or unsubstituted aliphatic ring; and n=1 or 2.

A silicon nitride powder to be used in a slurry for forming a mold release layer of a polycrystalline silicon casting mold, wherein the specific surface area thereof is 5-50 m.sup.2/g, the proportion of amorphous silicon nitride is 1.0-25.0 mass %, and the oxygen content is 0.6-2.5 mass %. A silicon nitride powder slurry for use in mold release material and capable of forming, on a polycrystalline silicon casting mold, a mold release layer which exhibits favorable mold release properties and exhibits favorable adhesion to the casting mold after casting the polycrystalline silicon ingot, and a method for producing the same. A silicon nitride powder for mold release material, a silicon nitride powder for a slurry use for obtaining the silicon nitride powder slurry for use in the mold release material, and a method for producing the same. A polycrystalline silicon casting mold which exhibits favorable mold release properties of a polycrystalline silicon ingot; and method for producing the same.

A silicon nitride powder to be used in a slurry for forming a mold release layer of a polycrystalline silicon casting mold, wherein the specific surface area thereof is 5-50 m.sup.2/g, the proportion of amorphous silicon nitride is 1.0-25.0 mass %, and the oxygen content is 0.6-2.5 mass %. A silicon nitride powder slurry for use in mold release material and capable of forming, on a polycrystalline silicon casting mold, a mold release layer which exhibits favorable mold release properties and exhibits favorable adhesion to the casting mold after casting the polycrystalline silicon ingot, and a method for producing the same. A silicon nitride powder for mold release material, a silicon nitride powder for a slurry use for obtaining the silicon nitride powder slurry for use in the mold release material, and a method for producing the same. A polycrystalline silicon casting mold which exhibits favorable mold release properties of a polycrystalline silicon ingot; and method for producing the same.

A powder sintering system is disclosed. The powder sintering system includes a furnace body, a first dispersing device, a second dispersing device, and a heating device. The furnace body includes a bottom and a side wall defines a funnel shaped chamber. The at least one first dispersing device is located on the bottom, and configured to centrifugally disperse and throw powder from the bottom to the side wall. The at least one second dispersing device is located on the side wall, and configured to centrifugally disperse and throw the powder from the side wall to a center of the funnel shaped chamber. The heating device is located outside the furnace body.

A silicon nitride substrate including silicon nitride crystal grains and a grain boundary phase and having a thermal conductivity of 50 W/m.Math.K or more, wherein, in a sectional structure of the silicon nitride substrate, a ratio (T2/T1) of a total length T2 of the grain boundary phase in a thickness direction with respect to a thickness T1 of the silicon nitride substrate is 0.01 to 0.30, and a variation from a dielectric strength mean value when measured by a four-terminal method in which electrodes are brought into contact with a front and a rear surfaces of the substrate is 20% or less. The dielectric strength mean value of the silicon nitride substrate can be 15 kV/rum or more. According to above structure, there can be obtained a silicon nitride substrate and a silicon nitride circuit board using the substrate in which variation in the dielectric strength is decreased.

A silicon nitride substrate including silicon nitride crystal grains and a grain boundary phase and having a thermal conductivity of 50 W/m.Math.K or more, wherein, in a sectional structure of the silicon nitride substrate, a ratio (T2/T1) of a total length T2 of the grain boundary phase in a thickness direction with respect to a thickness T1 of the silicon nitride substrate is 0.01 to 0.30, and a variation from a dielectric strength mean value when measured by a four-terminal method in which electrodes are brought into contact with a front and a rear surfaces of the substrate is 20% or less. The dielectric strength mean value of the silicon nitride substrate can be 15 kV/rum or more. According to above structure, there can be obtained a silicon nitride substrate and a silicon nitride circuit board using the substrate in which variation in the dielectric strength is decreased.

A rapid, centrifugal method to prepare polysilazanes and separate them from their ammonium halide-anhydrous, liquid ammonia by-product is coupled with several, alternative methods to recover ammonium halide and anhydrous, liquid ammonia from the by-product. Some reactive modes of by-product recovery lead to sodium chloride as the sole waste product or, optionally, to ammonia borane as a secondary product of the process.