Shin-etsu Chemical Co., Ltd.

Noboru Kimura

Takuma Kushihashi

Yoshihiro Kubota

Waichi Yamamura

Shoji Kano

Ryouji Iwai

Masaki Seki

Kazuhiro Yamaguchi

Akira Satoh

Kenji Satoh

Kazuyoshi Tamura

Yukio Kurosawa

Koji Hagiwara

Kenji Itou

Kazuhito Hirata

Mitsuhiro Kanai

Yoshihiko Shimizu

Waichi Shin Etsu Chemical Co Ltd Yamamura

A three-dimensional ceramic heater, such as a cylindrical ceramic heater, is proposed in which the conductive ceramic heating element is multi-furcated into lanes at least in the folded-back sections so that the electric current tends to flow in a more uniform and hence laminar manner with the effect that the localized over heating is suppressed greatly.

Three-dimensional ceramic heater

There is disclosed a heating elementcomprising: at least

Heating element

There is disclosed a heating elementcomprising:

There is disclosed a PBN container in which a conductive film is deposited on a surface of a body formed by depositing PBN (pyrolytic boron nitride), wherein, at least, an angle between a PBN cut face of the body and at least one wall surface adjacent to the PBN cut face is 20&#xb0;-80&#xb0;, and a method for producing a PBN (pyrolytic boron nitride) container comprising at least steps of depositing PBN to form a body, processing a PBN cut face of the formed body so that at least, an angle between the PBN cut face and at least one wall surface adjacent to the PBN cut face is 20&#xb0;-80&#xb0;, and coating a surface of the processed body with a conductive film. Thus, there can be provided a PBN container excellent in durability where a conductive film is laminated on a surface of a body formed by depositing PBN, and a method for producing the PBN container.

PBN container and method for producing PBN container

A ceramic heater including a plate member made of insulating ceramics in which one or more pair(s) of through-holes are formed, a rod member made of conductive ceramics with a power-supply terminal at one end. The rod member is inserted into the through hole in the plate member. A conductive layer made of conductive ceramics is formed on the plate member; and a coating layer made of insulating ceramics is formed on the conductive layer. One end face of the rod member has a same plane with a main surface of the plate member, the conductive layer has a heater pattern formed on the main surface of the plate member, and the rod members are electrically insulated not to be short-circuited to each other in the opposite main surface.

Ceramic heater and method for producing ceramic heater

A pyrolytic boron nirtride double container for a source of molecular beams used in molecular beam epitaxy, wherein the transmissivity of an inner container of the pyrolytic boron nitride double container with respect to light having a wave number of 2600 cmto 6500 cmis 90% or less of that of an outer container. The pyrolytic boron nitride double container, which enables molecular beams to generate stably with good temperature controllability and high heat efficiency and which can be used in a stable manner, is provided through a simple process and at low cost, so that molecular beam epitaxial growth can be stabilized, quality of the epitaxial film can be improved, and even though the rise and drop in the temperature of the material melt is repeated, or even at an emergency suspension of the operation, the trouble due to breakage of the container can be prevented.

Pyrolytic boron nitride double container and manufacture thereof

There is disclosed a pyrolytic boron nitride container for accommodating a material serving as a source of molecular beams for molecular beam epitaxy, wherein the transmissivity of the pyrolytic boron nitride container with respect to light having a wave number of 2600 cm,to 6500 cm,has a profile such that the transmissivity changes in the height direction of the container. The pyrolytic boron nitride container can be manufactured through a simple process and at low cost. The pyrolytic boron nitride container can prevent material melt from rising along the inner wall surface and prevent splashed material melt from adhering to the upper portion of the container. Further, the pyrolytic boron nitride container can stabilize molecular beam epitaxial growth and improve the quality of epitaxial film.

Pyrolytic boron nitride container and manufacture thereof

Disclosed is a crucible of pyrolytic boron nitride (PBN) for molecular beam epitaxy for melting of the source material, with which the troubles due to adhering of the molten source material in the form of drops caused on the quality of the epitaxial layer can be greatly decreased. Namely, the inner surface of the crucible is free from pits or other irregularities responsible to the adhering of the melt when the growth plane, which can be exposed by stripping of the surface layer of 0.50 mm thickness by cleavage, has a surface roughness Ra not exceeding 2.0 .mu.m and Rmax not exceeding 18 .mu.m. Such a PBN crucible can be prepared by the CVD method to deposit PBN on the surface of a graphite core of which the surface roughness Ra does not exceed 2 .mu.m.

Crucible of pyrolytic boron nitride for molecular beam epitaxy

There is disclosed a pyrolytic boron nitride container used for a Boat method in which material melt is retained In the container, and a crystal is grown while a temperature gradient is imparted to the material melt. The transmissivity of the pyrolytic boron nitride container with respect to light at a wave number ranging from 3700 cm.sup.-1 to 6500 cm.sup.-1 has a profile such that the transmissivity monotonously changes in the longitudinal direction of the container. The transmissivity profile is produced by imparting a pressure profile during manufacture of the container through deposition of pyrolytic boron nitride, by roughing the outer surface of the container such that the surface roughness has a profile, or by compounding pyrolytic boron nitride with a different material. It becomes possible to facilitate generation of a temperature gradient in material melt within the container and to facilitate control of a temperature profile in the container.

Pyrolytic boron nitride container, and manufacture thereof

An improvement is proposed in the preparation of, for example, a ceramic heater consisting of a substrate plate of boron nitride, a patterned layer of pyrolytic graphite (PG) on the substrate to serve as an electric resistance element and an overcoating layer of pyrolytic boron nitride (PBN) in a process comprising the steps of depositing PG on the substrate surface, pattern-wise removing the PG layer by mechanical working to form grooves and depositing PBN all over. According to the inventive improvement, which can be obtained by forming the grooves in such a fashion that the angle between the direction of a normal line to the facet surface formed by the mechanical working and the growing direction of the substrate of boron nitride is in the range from 0.degree. to 45.degree. so that the internal stress caused in the overcoating layer, which is due to the anisotropy in the thermal expansion of boron nitride, is decreased to prevent the overcoating layer from occurrence of cracks and falling during service.

Method for the preparation of a double-coated body of boron nitride

A pyrolytic boron nitride crucible is disclosed which is suitable for producing a single crystal of a semiconductor compound of Group III and V by the LEC method. The crucible comprises a side part and a bottom part. The bottom part has an absorption coefficient of light of wavelengths between 3,700 cm.sup.-1 and 6,500 cm.sup.-1 of at most 1.7 and/or the absorption coefficient of light of wavelengths between 3,700 cm.sup.-1 to 6,500 cm.sup.-1 of the bottom part is less than that of the side part by at least 0.5. In the crucible, the heat conduction from the bottom part to material melt in the crucible is strengthened, so that the convection flow of the material melt is suppressed and the temperature distribution in the crucible can be easily controlled.

Pyrolytic boron nitride crucible

An improvement is proposed in the method for the preparation of a ceramic heater consisting of a substrate of boron nitride, patterned graphite layer thereon as an electric resistance heater element and an overall cladding layer of pyrolytic boron nitride formed on allover the surface after pattern-wise engraving of the graphite layer and the substrate in order to enhance the stability of the cladding layer against crack formation or exfoliation. The improvement is achieved by limiting the depth of engraving not to exceed 200 .mu.m or chamfering and rounding of the edged and recessed ridge lines formed by engraving so that the cross sectional profile is in a smooth contour having a radius of curvature not smaller than 0.5 mm.

Method for the preparation of pyrolytic boron nitride-clad double-coated

Proposed is a novel vessel such as crucibles made from PBN (pyrolytic boron nitride), which is highly resistant against exfoliation of the surface layer and suitable for use, for example, as a container of the melt in the Czochralski single crystal growing of III-V Group compound semiconductor single crystals with an improvement in the serviceable life. The PBN-made vessel of the invention is characterized by specific values of several parameters including density, which should be in the range from 1.90 to 2.05 g/cm.sup.3, intensity ratio of the X-ray diffraction peaks representing the degree of orientation, heat conductivity coefficient and the like. The above mentioned advantageous serviceable life of the vessel can be obtained only when these parameter values are satisfied.

Vessel made from pyrolytic boron nitride

Proposed is an article of pyrolytic boron nitride such as crucibles for use at a high temperature under an extremely high vacuum as in the molecular beam epitaxy. The article can be used in the high temperature, high vacuum process without the conventional elaborate and time-consuming degassing bake-out treatment because the article is wrapped in a wrapping film having a specified low moisture permeability immediately after a preliminary degassing treatment under specified conditions before the article is wrapped under a low-moisture atmosphere in a glove box.

Growing community of inventors

Gunma, Japan

Noboru Kimura