Semiconductor memory device having improved isolation between
electrodes, and process for fabricating the same

    公开(公告)号:US5736449A

    公开(公告)日:1998-04-07

    申请号:US592464

    申请日:1996-01-26

    摘要: With recent decreases in the size of semiconductor memories, isolation problems typically arise during fabrication of a capacitor for a high-capacity semiconductor memory device. To overcome this, arrangements are provided to improve the isolation between capacitor elements even if those elements are extremely close together. For example, if a material such as platinum is used as a capacitor bottom electrode, a thin layer of titanium oxide can be deposited before forming the platinum, to provide a structure in which the titanium oxide is on the bottom portion of the trench. A high-dielectric-constant insulator is then formed over that structure by the Chemical Vapor Deposition. The high-dielectric-constant insulator has a composition which satisfies the stoichiometric composition over the platinum and which has more titanium atoms than those of the stoichiometric composition on the trench bottom. The resulting non-stoichiometric composition layer formed on the trench bottom has a low dielectric constant and a high insulation to maintain electric insulation between adjoining bottom capacitor electrodes. Because of a low crystallization, moreover, a layer having a planarized morphology is formed.

    Apnea preventive stimulating device
    62.
    发明授权
    Apnea preventive stimulating device 失效
    APNEA预防性刺激装置

    公开(公告)号:US5178156A

    公开(公告)日:1993-01-12

    申请号:US537028

    申请日:1990-06-12

    IPC分类号: A61B5/08 A61N1/18 A61N1/36

    CPC分类号: A61N1/3601

    摘要: The sleep-apnea syndrome is classified into a so-called central type caused by an abnormality in the respiratory center, an obstructive type by an upper airway obstruction, and a mixed type by a combination thereof. Among the rest, the obstructive type is often observed clinically and is considered to be caused by a morphological abnormality in the upper airway tract, such as tonsillar hypertrophy or micrognathia, or by a tonus of the upper airway muscle for broadening the airway. The inventors of this application have clarified by experiments that the upper airway can be recovered from obstruction which causes apnea stimulating the genioglossus, which is one of the dilator muscles of the upper airway, with pulses of a frequency of 40 to 150 Hz, a peak value of 1 to 50 volts and a rise-up time constant of 0.2 seconds or more, and that control of the start and stop of the electric stimulation with apnea detection signals would make it possible to automatically take measures to deal with apnea even at night when it is particularly difficult to find a fit of apnea.

    Photocoupler circuit having DC power source in series with detection and
switching means
    63.
    发明授权
    Photocoupler circuit having DC power source in series with detection and switching means 失效
    具有与检测和开关装置串联的直流电源的光电耦合电路

    公开(公告)号:US5043587A

    公开(公告)日:1991-08-27

    申请号:US466492

    申请日:1990-01-17

    CPC分类号: H03K17/7955

    摘要: Provided is an enhanced switching speed photo-coupler circuit for providing an output signal in response to an isolated input signal. The photocoupler is comprised of a phototransistor which operates in the active region in response to an applied input signal. A switching transistor connected to the output of the phototransistor is turned on when the phototransistor enters the active region. An output signal, measured from the collector of the switching transistor, will change only slightly in comparison with the off state. In one embodiment, a power semiconductor is coupled to the circuit output for enhanced switching speed.