摘要:
A reactor vessel includes a quartz glass body having sidewalls and a ceiling formed as a single unit without welds. Translucent or opaque portions are formed by bubbles in the glass where heat insulation is desired and transparent portions are formed by absence of bubbles where heat transmission and visibility are desired. The body is formed by adding quartz glass powder to a mold which is rotated about a central axis so that centrifugal force causes a layer of powder to form on the inside of the mold. The layer is then heated until it melts.
摘要:
An object of the present invention is to provide a lapping machine in which abrasive grains can be efficiently and completely removed from a lapping plate. In the lapping machine of the present invention, a lapping plate has a lapping face and rotates about a rotary shaft. A moving member has a wiping face extended in a longitudinal and moves, in a plane parallel to the lapping face of the lapping plate, in the direction perpendicular to the wiping face. A driving mechanism moves the moving member. With this structure, the moving member securely catches and removes foreign substances from the lapping plate. The foreign substances left can be completely removed in a short time and the working efficiency of the lapping steps can be highly improved.
摘要:
A light-weight base body of a reflecting mirror, such as those used in reflecting astronomical telescopes, is proposed which is made from fused silica glass or high-silica glass and is advantageous in respect of the excellent thermal and mechanical stability in dimensions to ensure high performance of the reflecting mirror. The base body is composed of a front plate, i.e. a surface plate to provide the optical surface, and a supporting body of porous foamed glass integrally bonded to the front plate. These two parts of the base body can be bonded together by sandwiching a layer of a finely divided silica powder therebetween and heating the assemblage at a temperature higher than the softening point of the silica powder so that the silica powder is softened or melted to firmly join the two parts sandwiching the powder layer. The base body can be further improved in respect of the mechanical stability by providing a rear plate backing the porous foamed body and a reinforcing hoop-like side layer surrounding the side surface of the porous foamed body, each made from fused quartz glass or high-silica glass and bonded to the porous foamed body by utilizing melting of a layer of silica powder therebetween.
摘要:
A method for producing a memory LSI having in its peripheral circuitry an MISFET of LDD structure and a vertical type bipolar transistor is disclosed. More particularly, an impurity for forming a low impurity concentration region of the said MISFET of LDD structure is introduced sideways of an emitter-base junction of the bipolar transistor. By the introduction of the said impurity, an effective impurity concentration near the base surface is reduced and the cut-off frequency of the bipolar transistor is improved.
摘要:
A semiconductor integrated circuit comprising first n-channel MISFETs constituting the memory cells of a storage system, second n-channel MISFETs constituting the peripheral circuits of the storage system, and third n-channel MISFETs constituting the output circuit among the peripheral circuits. The respective threshold voltages of the first n-channel MISFETs, the second n-channel MISFETs and the third n-channel MISFETs are decreased in that order when the respective gate lengths of those MISFETs are substantially the same.
摘要:
A light-weight base body of a reflecting mirror, such as those used in reflecting astronomical telescopes, is proposed which is made from fused silica glass or high-silica glass and is advantageous in respect of the excellent thermal and mechanical stability in dimensions to ensure high performance of the reflecting mirror. The base body is composed of a front plate, i.e. a surface plate to provide the optical surface, and a supporting body of porous foamed glass integrally bonded to the front plate. These two parts of the base body can be bonded together by sandwiching a layer of a finely divided silica powder therebetween and heating the assemblage at a temperature higher than the softening point of the silica powder so that the silica powder is softened or melted to firmly join the two parts sandwiching the powder layer. The base body can be further improved in respect of the mechanical stability by providing a rear plate backing the porous foamed body and a reinforcing hoop-like side layer surrounding the side surface of the porous foamed body, each made from fused quartz glass or high-silica glass and bonded to the porous foamed body by utilizing melting of a layer of silica powder therebetween.
摘要:
A D-RAM is disclosed which isolates the capacitors of memory cells and also isolates the adjacent memory cells by utilizing trenches formed on a semiconductor substrate. The device is particularly intended to the area of each memory cell and prevent the occurrence of a leakage current between the adjacent memory cells. Two side walls of the trench are used as the capacitors of two different memory cells, respectively, and these capacitors are isolated from each other by a thick oxide film that is formed on the bottom of each trench.
摘要:
In a semiconductor memory circuit device wherein each memory cell is constituted by a series circuit of a memory cell selecting MISFET and an information storing capacitor of a stacked structure, there are present in a first region as a memory cell array region a first MISFET having a gate electrode and source and drain regions; first and second capacity electrodes and a dielectric film extending onto a first insulating film on the gate electrode; a second insulating film positioned on the second capacity electrode; and a first wiring positioned on the second insulating film, while in a second region as a peripheral circuit region there are present a second MISFET having a gate electrode and source and drain regions; a first insulating film on the gate electrode; a third insulating film on the first insulating film; a second insulating film on the third insulating film; and a second wiring on the second insulating film.
摘要:
In a semiconductor memory circuit device wherein each memory cell is constituted by a series circuit of a memory cell selecting MISFET and an information storing capacitor of a stacked structure, there are present in a first region as a memory cell array region a first MISFET having a gate electrode and source and drain regions; first and second capacity electrodes and a dielectric film extending onto a first insulating film on the gate electrode; a second insulating film positioned on the second capacity electrode; and a first wiring positioned on the second insulating film, while in a second region as a peripheral circuit region there are present a second MISFET having a gate electrode and source and drain regions; a first insulating film on the gate electrode; a third insulating film on the first insulating film; a second insulating film on the third insulating film; and a second wiring on the second insulating film.
摘要:
A semiconductor integrated circuit device includes a dielectric breakdown prevention circuit coupled to an external terminal for protecting an input stage circuit. The prevention circuit has bipolar transistors and complementary MISFETs including a first MISFET of a first conductivity type and a second MISFET of a second conductivity type. A first semiconductor region of the first conductivity type is formed by the same layer as a well region in which the second MISFET is formed. A second semiconductor region of the second conductivity type is formed in said first semiconductor region by the same layer as source and drain regions of the second MISFET. These first and second semiconductor regions form a first PN junction diode. The external terminal is electrically coupled to one end portion of said second semiconductor region. A high impurity conductivity type buried third semiconductor region underlies the said second semiconductor region, and is formed by the same layer as a region isolating the bipolar transistors. This third region is disposed at the bottom surface of said first semiconductor region. A fourth semiconductor region of the second conductivity type is also formed in said first semiconductor region by the same layer used for collector contact regions of the bipolar transistors, and is connected with another end portion of said second semiconductor region, in contact with the third semiconductor region. The fourth semiconductor region is coupled to the input stage circuit, and the third and fourth semiconductor regions form a second PN junction diode.