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[Author] Kiyotaka KOMOKU(7hit)

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  • A CMOS Temperature Sensor Circuit

    Takashi OHZONE  Tatsuaki SADAMOTO  Takayuki MORISHITA  Kiyotaka KOMOKU  Toshihiro MATSUDA  Hideyuki IWATA  

     
    PAPER-Integrated Electronics

      Vol:
    E90-C No:4
      Page(s):
    895-902

    A supply voltage (VDD) independent temperature sensor circuit, which can be realized by the optimum combination of three current modes of n-MOSFETs including the subthreshold current using the feedback scheme from the temperature dependent voltage (VTD) output to the gates of three n-MOSFETs, was proposed and fabricated by a standard 1.2 µm n-well CMOS process. The circuit consists of only 17 MOSFETs without high resistors resulting in a small die area of 0.18 mm2. The temperature coefficient TC of the sensor circuit can be controlled by the channel length ratio L4/L3 of two n-MOSFETs. The average temperature sensor voltage VTS and its typical TC are 1.77 V at VDD=5.0 V (20) and 5.1 mV/ for VDD=5.01.0 V in the temperature range of -20-100 in case of L4/L3=9, respectively.

  • Modeling and Layout Optimization of MOM Capacitor for High-Frequency Applications

    Yuka ITANO  Taishi KITANO  Yuta SAKAMOTO  Kiyotaka KOMOKU  Takayuki MORISHITA  Nobuyuki ITOH  

     
    LETTER

      Vol:
    E101-A No:2
      Page(s):
    441-446

    In this work, the metal-oxide-metal (MOM) capacitor in the scaled CMOS process has been modeled at high frequencies using an EM simulator, and its layout has been optimized. The modeled parasitic resistance consists of four components, and the modeled parasitic inductance consists of the comb inductance and many mutual inductances. Each component of the parasitic resistance and inductance show different degrees of dependence on the finger length and on the number of fingers. The substrate network parameters also have optimum points. As such, the geometric dependence of the characteristics of the MOM capacitor is investigated and the optimum layout in the constant-capacitance case is proposed by calculating the results of the model. The proposed MOM capacitor structures for 50fF at f =60GHz are L =5μm with M =3, and, L =2μm with M =5 and that for 100fF at f =30GHz are L =9μm with M =3, and L =4μm with M =5. The target process is 65-nm CMOS.

  • A Test Structure to Analyze Highly-Doped-Drain and Lightly-Doped-Drain in CMOSFET

    Takashi OHZONE  Kazuhiko OKADA  Takayuki MORISHITA  Kiyotaka KOMOKU  Toshihiro MATSUDA  Hideyuki IWATA  

     
    PAPER-Semiconductor Materials and Devices

      Vol:
    E89-C No:9
      Page(s):
    1351-1357

    A test structure to separately measure sheet resistances of highly-doped-drain (HDD) and lightly-doped-drain (LDD) in LDD-type CMOSFETs with various gate spaces S having sub-100 nm sidewalls was proposed. From the reciprocal of source/drain-resistance R-1 versus S characteristics, the sheet resistance ρH of the high-conductive-region (HCR) corresponding to HDD and the approximate width WLC of the low-conductive-region (LCR) corresponding to LDD could be estimated. Both of ρH and WLC for p- and n-MOS devices were scarcely dependent on the gate voltage. The sidewall-width difference of 40 nm could be sufficiently detected by using the test structure with the S pitch of about 60 nm. The R-1 versus S characteristics showed the unstable resistance variations in the narrow S region less than 0.3 µm, which corresponded to the minimum S for the process used for the test device fabrication and suggested that various micro-loading effects seriously affected on the characteristics.

  • A Test Structure to Analyze Electrical CMOSFET Reliabilities between Center and Edge along the Channel Width

    Takashi OHZONE  Eiji ISHII  Takayuki MORISHITA  Kiyotaka KOMOKU  Toshihiro MATSUDA  Hideyuki IWATA  

     
    PAPER-Semiconductor Materials and Devices

      Vol:
    E90-C No:2
      Page(s):
    515-522

    A test structure to separately analyze the location where the hot-carrier-induced CMOSFET reliability is determined around the center or the isolation-edge along the channel-width was proposed and fabricated. The test structure has four kinds of MOSFETs; [A] and [D] MOSFETs with a short and a long channel-length all over the channel width, respectively, [B] MOSFET with the short and the long channel-length around the center and the both isolation-edges, respectively, and [C] MOSFET with the channel-length regions vice versa to the [B] MOSFET. The time dependent changes of the threshold voltages VT, the saturation currents IS, the linear currents IL and the maximum transconductances β up to 50,000 s were measured. All data for the wide channel-width MOSFETs were almost categorized into three; [A], [B]/[C] and [D]. The [B]/[C] data were well estimated from simple theoretical discussions by the combination of [A] and [D] data, which mean that the reliabilities are nearly the same around the center or the isolation-edge for the CMOSFETs.

  • Current-Voltage Hysteresis Characteristics in MOS Capacitors with Si-Implanted Oxide

    Toshihiro MATSUDA  Shinsuke ISHIMARU  Shingo NOHARA  Hideyuki IWATA  Kiyotaka KOMOKU  Takayuki MORISHITA  Takashi OHZONE  

     
    PAPER-Semiconductor Materials and Devices

      Vol:
    E92-C No:12
      Page(s):
    1523-1530

    MOS capacitors with Si-implanted thermal oxide and CVD deposited oxide of 30 nm thickness were fabricated for applications of non-volatile memory and electroluminescence devices. Current-voltage (I-V) and I-V hysteresis characteristics were measured, and the hysteresis window (HW) and the integrated charge of HW (ICHW) extracted from the hysteresis data were discussed. The HW characteristics of high Si dose samples showed the asymmetrical double-peaks curves with the hump in both tails. The ICHW almost converged after the 4th cycle and had the voltage sweep speed dependence. All +ICHW and -ICHW characteristics were closely related to the static (+I)-(+VG) and (-I)-(-VG) curves, respectively. For the high Si dose samples, the clear hump currents in the static I-VG characteristics contribute to lower the rising voltage and to steepen the ICHW increase, which correspond to the large stored charge in the oxide.

  • A Study of Striped Inductor for K- and Ka-Band Voltage-Controlled Oscillators Open Access

    Nobuyuki ITOH  Hiroki TSUJI  Yuka ITANO  Takayuki MORISHITA  Kiyotaka KOMOKU  Sadayuki YOSHITOMI  

     
    INVITED PAPER

      Vol:
    E99-C No:6
      Page(s):
    614-622

    A striped inductor and its utilization of a voltage-controlled oscillator (VCO) are studied with the aim of suppressing phase noise degradation in K- and Ka-bands. The proposed striped inductor exhibits reduced series resistance in the high frequency region by increasing the cross-sectional peripheral length, as with the Litz wire, and the VCO of the striped inductor simultaneously exhibits a lower phase noise than that of the conventional inductor. Striped and conventional inductors and VCOs are designed and fabricated, and their use of K- and Ka-bands is measured. Results show that the Q factor and corner frequency of the striped inductor are approximately 1.3 and 1.6 times higher, respectively, than that of the conventional inductor. Moreover, the 1-MHz-offset phase noise of the striped inductor's VCO in the K- and Ka-bands was approximately 3.5 dB lower than that of the conventional inductor. In this study, a 65-nm standard CMOS process was used.

  • A Test Structure for Asymmetry and Orientation Dependence Analysis of CMOSFETs

    Toshihiro MATSUDA  Yuya SUGIYAMA  Keita NOHARA  Kazuhiro MORITA  Hideyuki IWATA  Takashi OHZONE  Takayuki MORISHITA  Kiyotaka KOMOKU  

     
    PAPER

      Vol:
    E91-C No:8
      Page(s):
    1331-1337

    A test structure to analyze asymmetry and orientation dependence of MOSFETs is presented. n-MOSFETs with 8 different channel orientation and three kinds of process conditions were measured and symmetry characteristics of IDsat and IBmax with respect to the interchange of source and drain was examined. Although both IDsat and IBmax have similar channel orientation dependence, IBmax in interchanged S/D measurements shows asymmetrical characteristics, which can be applied to a sensitive method for device asymmetry detection.