公开(公告)号：JPH10335447A

公开(公告)日：1998-12-18

申请号：JP14171797

申请日：1997-05-30

Applicant: MATSUSHITA ELECTRIC WORKS LTD

Inventor： OGIWARA ATSUSHI ,  OKA NAOMASA ,  OKUTO TAKASHI ,  KAMAKURA MASATOMO

IPC: H01L21/762 ,  H01L21/02 ,  H01L21/76 ,  H01L27/12

Abstract: PROBLEM TO BE SOLVED: To provide a method for manufacturing a dielectric isolation substrate which can prevent generation of a void at a tip end of a V-shaped groove. SOLUTION: A polysilicon layer 5a is formed as deposited on a side of a single crystal silicon substrate 1 having a groove 1a made therein by a CD process using trichlorosilane and hydrogen gases as source gases. At this time, a temperature within a reactor where the polysilicon layer 5a is to be deposited is previously set at less than 1150 deg.C. Next, the temperature within the reactor is set at 1150 deg.C or more without causing any change in the flow rates of the source gases, to thereby form an upper polysilicon layer 5b through deposition. Finally, the substrate is polished from a side of the substrate not provided with the layer 5b until the layer 5a buried in the groove 1a is exposed, to thereby silicon single crystal islands 6 of the substrate 1 covered on its bottom and side faces with a silicon oxide film 4. That is, the layer 5b is polished down to a predetermined thickness.

公开(公告)号：JPH08236475A

公开(公告)日：1996-09-13

申请号：JP3485395

申请日：1995-02-23

Applicant: MATSUSHITA ELECTRIC WORKS LTD

Inventor： KENO TAKUJI ,  OGIWARA ATSUSHI ,  EDA KAZUO

IPC: H01L21/28 ,  H01L21/306

Abstract: PURPOSE: To stably form a contact window which has an excellent electrode coverage. CONSTITUTION: After a single-crystal silicon oxide film 11 is formed on the surface of a semiconductor substrate 10, a polycrystalline silicon film 12 containing no dopant and single-crystal silicon nitride film 13 are successively formed on the film 11. The nitride film 13 is then removed from the forming area of a contact window 16 and the film 12 in the forming area is thermally oxidized. After oxidizing the film 12, oxide films 15 and 11 are removed from the forming area by using a fluorine-based etchant and the nitride film is removed from the same area. Therefore, the edge section of the window 16 becomes smooth.

公开(公告)号：JPH0864754A

公开(公告)日：1996-03-08

申请号：JP19999694

申请日：1994-08-25

Applicant: MATSUSHITA ELECTRIC WORKS LTD

Inventor： OGIWARA ATSUSHI

IPC: H01L29/73 ,  H01L21/331 ,  H01L21/822 ,  H01L23/58 ,  H01L27/04

Abstract: PURPOSE: To provide the structure of an overheat detecting circuit which can be formed into small size at low cost. CONSTITUTION: An overheat detecting circuit is provided with a reverse biased diode 1 and an NPN transistor 3 which is connected in such a manner that the leak current of the diode 1 becomes its base current, and the abnormal temperature of a power device is detected by considering the increase in leakage current of the diode 1 due to temperature rise as the change of working point of the NPN transistor 3. Accordingly, the overheat detecting circuit of small size can be formed at low cost by forming the diode 1 and the NPN transistor 3 on the same semiconductor substrate as the power device or a power device driving integrated circuit.

公开(公告)号：JPH07235663A

公开(公告)日：1995-09-05

申请号：JP2517494

申请日：1994-02-23

Applicant: MATSUSHITA ELECTRIC WORKS LTD

Inventor： OGIWARA ATSUSHI

IPC: H01L29/74

Abstract: PURPOSE:To decrease the sensitivity of a gate and to prevent the erroneous operation by forming a high-density region of lattice defects wherein the density of the lattice defects is locally enhanced at the P-N junction comprising a gate region and a cathode region. CONSTITUTION:In a static-induction type thyristor, a region having the high density of lattice defects (a high lattice-defect density region 10) is intentionally introduced at a P-N junction 9 comprising a gate region 4 and a cathode region 5. Thus the rise-up of a current becomes quick in the forward voltage-current characteristic between the gate and the cathode. The initial current is the wattless current and does not contribute to the turn-on of the static-induction type thyristor. Therefore, the gate sensitivity of the static-induction type thyristor can be lowered. Thus, the high-density lattice defects are introduced at the P-N junction comprising the gate region and the cathode region. Therefore, the minimum gate current to obtain turn-on can be increased, and the gate sensitivity can be decreased. The erroneous operation caused by a noise voltage can be prevented.

公开(公告)号：JPH0661817A

公开(公告)日：1994-03-04

申请号：JP21593392

申请日：1992-08-13

Applicant: MATSUSHITA ELECTRIC WORKS LTD

Inventor： OGIWARA ATSUSHI ,  HAYAZAKI YOSHIKI

IPC: H03K17/08 ,  H03K17/73

Abstract: PURPOSE:To obtain an overcurrent detection circuit for an electrostatic induction thyristor without any loss. CONSTITUTION:An output of a comparator 5 goes to a high level when an electrostatic induction thyristor 10 is turned on. An output of a comparator 6 goes to a high level when a level of a noninverting input terminal is higher than a reference level Vref. The potential at the noninverting input terminal 10 of the comparator 6 is nearly equal to a potential of an anode of the electrostatic induction thyristor 10 so long as the electrostatic induction thyristor 10 is turned on. Thus, when an overcurrent flows to the electrostatic induction thyristor 10 and the potential at the noninverting input terminal of the comparator 6 exceeds the reference level Vref, an AND gate 7 receives high level outputs from both the comparators 5, 6 and outputs a high level gate output. A gate drive circuit 8 receives the gate output to turn off the electrostatic induction thyristor 10.

公开(公告)号：JPH04373306A

公开(公告)日：1992-12-25

申请号：JP15143191

申请日：1991-06-24

Applicant: MATSUSHITA ELECTRIC WORKS LTD

Inventor： OGIWARA ATSUSHI

IPC: H03K17/73

Abstract: PURPOSE:To hardly generate error ignition caused by noise or the like. CONSTITUTION:The point of connecting one of first switching elements 12 in the relation of inverted ON/OFF and one of second switching elements 13 is connected through a parallel circuit 3, which is composed of a resistor 14 and a capacitor 15, to the gate of an electrostatic induced thyristor 20, a plus Vcc of a DC voltage is impressed to the other first switching element 12, and the minus DC voltage is impressed to the other second switching element 13 and the cathode of the electrostatic induced thyristor 20. In such a driving circuit 1 of the electrostatic induced thyristor 20, a DC power source 17 and a third switching element 16, which is turned on when the first switching element 12 is turned off, are provided and connected so that the voltage of the DC power source is reversely biased between the gate and cathode of the electrostatic induced thyristor 20 through the third switching element 16.