摘要:
A field-effect transistor or a bipolar transistor may be provided in which the contact resistance between a channel layer or base layer and a contact layer are reduced. For example, an InGaAs buffer layer may be formed on the substrate side of an InGaAs channel layer of a field-effect transistor and by the bypassing effect that carriers pass through this InGaAs buffer layer, the InGaAs channel layer comes in contact with the contact layer with a low resistance. The contact resistance between the InGaAs channel layer and the contact layer can be reduced to 10 ohm per a width of 10.mu.m, and as a result, the value of transconductance factor K of a field-effect transistor can be increased in 14 mA/V.sup.2 per a width of 10.mu.m.
摘要:
This invention discloses a heterojunction type field effect transistor such as 2DEG-FET and a heterojunction type bipolar transistor such as 2DEG-HBT. The former is fabricated by applying to the formation of its source and drain regions a technique which causes the disorder of the heterojunction by intoduction of an impurity such as by ion implantation or a technique which causes the disorder of the heterojunction by forming a film made of at least one kind of material selected from insulators, metals and semiconductors which have a different linear coefficient of thermal expansion from that of the material of a semiconductor substrate on the heterojunction semiconductor region which is to be disordered. The latter is fabricated by applying either of the techniques described above to a base ohmic contact region. These semiconductor devices can reduce the source-gate resistance and the parasitic base resistance. The invention discloses also the structure of the ohmic contact layer which has a trench on the surface thereof and is particularly effective for reducing the source-gate parasitic resistance.
摘要:
A solid film forming apparatus, e.g., an MO-MBE (Metal-Organic Molecular Beam Epitaxy) apparatus, wherein evacuatable containers isolated from a growth chamber by a switching device and connected to raw material gas introduction pipings are provided between the growth chamber for a solid film, e.g., a compound semiconductor, and raw material gas introduction pipings. Growth of the solid film is controlled by opening and closing the switching device and evacuating the container at least while the switching device is closed during the growth of the solid film. An undesired influence on the growing film due to residual gas in the containers which are not used for growth can be prevented and, hence, interception and introduction of the raw material gas into the growth chamber can be performed with remarkably high controllability, and films of superior abruptness of the interface between films, e.g., the heterojunction of the compound semiconductor, can be obtained.
摘要:
This invention discloses a heterojunction type field effect transistor such as 2DEG-FET and a heterojunction type bipolar transistor such as 2DEG-HBT. The former is fabricated by applying to the formation of its source and drain regions a technique which causes the disorder of the heterojunction by introduction of an impurity such as by ion implantation or a technique which causes the disorder of the heterojunction by forming a film made of at least one kind of material selected from insulators, metals and semiconductors which have a different linear coefficient of thermal expansion from that of the material of a semiconductor substrate on the heterojunction semiconductor region which is to be disordered. The latter is fabricated by applying either of the techniques described above to a base ohmic contact region. These semiconductor devices can reduce the source-gate resistance and the parasitic base resistance. The invention discloses also the structure of the ohmic contact layer which has a trench on the surface thereof and is particularly effective for reducing the source-gate parasitic resistance.
摘要:
A method of fabricating a rubber double-toothed belt wherein the unvulcanized rubber thereof is firstly heat treated so as to define a first toothed portion of the belt without substantial vulcanization thereof. The preform is then entrained about pulleys and a pair of heated molds engaged with both the toothed portion and the nontoothed outer portion of the belt to place the preform under pressure at a vulcanization temperature for sufficient time to cause the outer rubber portion of the preform to flow outwardly and define the outer teeth of the final belt concurrently with the vulcanization of the double-toothed belt construction. The parameters for controlling the heat treatment to provide the configurational retention without substantial vulcanization of the preform rubber are disclosed.
摘要:
A method of forming a double timing belt wherein a belt preform is firstly formed with teeth on one face thereof. The opposite face of the belt in which the tensile cord is embedded is provided with oppositely projecting teeth in accurate alignment with the teeth of the preform by a successive molding of pluralities of such teeth to the opposite face, with the preform entrained about a pair of adjustably spaced toothed pulleys. Accurate uniform pitch line difference is maintained by providing shims between the mold and belt support during the molding of the second set of teeth to the preform. The mold and support are retained in accurate alignment by cooperating dowels and recesses on the support and mold members. Cooling devices are provided at opposite ends of the mold for preventing full vulcanization of the tooth rubber thereat.
摘要:
A method of forming a belt/belt sleeve having a length and teeth spaced lengthwise of the belt/belt sleeve. The method includes the steps of providing a cylindrical cloth having a sewn joint; providing a mold having an axis, a circumference, and a plurality of axially extending grooves spaced around the circumference of the mold; extending the cylindrical cloth around the mold; providing a rod; pressing the rod against the cloth at the sewn joint so as to urge the sewn joint into one of the axially extending grooves; separating the rod from the cloth; and forming at least one belt component around the cloth on the mold after the rod is separated from the cloth.
摘要:
In a method of selectively growing a crystal of a compound semiconductor layer which is composed of gallium and arsenic, a selective growth is selectively carried out on a substrate by using a combination of metallic gallium and a reactive gas, such as trisdimethylminoarsine, which includes a metallic compound of arsenic specified by at least one amine. The combination may includes organometallic gallium, such as trimethylgallium, triethylgallium instead of the metallic gallium. Such a combination serves to selectively deposit the compound semiconductor layer only on an exposed portion uncovered with a mask. Any other compound semiconductor layer may be selectively deposited on the exposed portion. The exposed portion may be composed of GaAs, AlGaAs, or InGaAs.
摘要:
This disclosure is concerned with a method for treating a stainless steel surface by high temperature oxidation. The surface of a stainless steel article is cleaned. TiO.sub.2 and SiO.sub.2 are mixed in microparticles to form a coating agent, and water is added to the mixture to make a slip. The slip is coated on the steel surface to form a coating having a uniform thickness. The coating is dried and the article is subjected to a heat-treatment to form an oxide film. This treatment is performed in an oxidizing atmosphere for a time and a temperature suitable for the color tone to be produced. A desirable temperature for the heat-treatment is between 350.degree. C. to 700.degree. C. When a coating agent is used, it is later removed by washing, etc. after cooling the article.Further, when less dissolution of iron from the stainless steel surface is required, a decolorization treatment is applied; that is, the colored oxide film is removed from the surface by dissolution using an acid or an electrolytic treatment.
摘要:
A method of manufacturing glass-lined tube. An undercoat of glass is fused onto the surfaces of nozzle-shaped flange-pieces, from their outer peripheral edges to their molded and curved inner faces, welding flange components then welded to either end of the metal tube to form a complete flange at each end. The inner faces of the weld zones are then shaped by grinding and polishing. A glass tube that is greater in length than the metal tube is fitted loosely into the latter tube. The glass tube is supported at either end within the wells of conical caps which are fitted around the flanges by air-permeable spacer-rings, with the ends of the glass tube extending beyond the outward faces of the flange joints and with the glass tube being securely positioned at the center line of the metal tube. The entire assembly is heated so that the glass tube will soften and expand under the influence of internal pressure, thus providing a continuous covering of the inner surface of the metal tube extending to the surface of the flange junction.