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Direct-Type Silicon Pixel Detector for a Large-Area Hybrid X-Ray Imaging Device
박건식,박종문,유성욱,윤용선,강진영,김보우,김태우,J. Kosonen,윤창주,노광수 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.4
We demonstrated the design and the fabrication processes of a direct-type silicon pixel detector for a digital dental radiograph made by using a high-resistivity n-type silicon substrate. The structure of the detector is based on a fully-depleted p-i-n diode. The detector is composed of 644,328 pixels with a pitch of 35 ∽ 35 μm. The size of the detector is 2.58 ∽ 3.47 cm and it is composed of a 4-block assembly with four read-out complementary metal-oxide semiconductor integrated circuits (CMOS ICs). We focused on experimentally evaluating the process conditions for the silicon pixel detector to reduce the leakage current and to increase the breakdown voltage. From the experimental results, we found that a high-temperature drive-in after p+ ion implantation deteriorates the leakage current and that a p+ passivation by thermal oxidation increases the breakdown voltage. The leakage current of the detector was 5.7 nA/cm2 (0.07 pA/pixel) and the breakdown voltage was more than 1700 V. The read-out IC consists of a current-integrating pixel readout CMOS chip and PbSn bumps. After four read-out ICs had been bump-bonded to a pixel detector and wire-bonded to a printed circuit board (PCB), X-ray images showed a resolution of 9 lp/mm and provided a good image of human teeth.
朴建植,池善豪 최신의학사 1974 最新醫學 Vol.17 No.12
In an attempt to evaluate cranioplasty, authors reviewed 53 cases of head injuries with cranial defect repaired by cranioplasty. Materials used for cranioplasty were acrylic resin in 42 cases, tantalum in 6 cases and iliac bone in 5 cases. Adequate follow-up observations were obtained in all cases for at least 4 years. The results were as follows; 1) The majority of head injuries were caused by vehicle accident. 2) The majority of skull defects were in the frontal and parietal bones. 3) The interval between primary craniectomy and secondary cranioplasty was from 3 to 4 months in the majority of cases and cranioplasty was performed after fixation of permanent neurologic defect. 4) The indications for the cranioplasty were based upon criteria recommended by Grant and Norcross. 5) Postoperative complications were observed in 3 cases (5.7%).
Boron 확산공정을 이용한 5,000V, 4인치 광 사이리스터의 제작 및 특성 평가
박건식,조두형,원종일,이병하,배영석,구인수 전력전자학회 2019 전력전자학회 논문지 Vol.24 No.6
Light-triggered thyristors (LTTs) are essential components in high-power applications, such as HVDC transmission and several pulsed-power applications. Generally, LTT fabrication includes a deep diffusion of aluminum as a p-type dopant to form a uniform p-base region, which needs careful concern for contamination and additional facilities in silicon semiconductor manufacturing factories. We fabricated 4-inch 5,000 V LTTs with boron implantation and diffusion process as a p-type dopant. The LTT contains a main cathode region, edge termination designed with a variation of lateral doping, breakover diode, integrated resistor, photosensitive area, and dV/dt protection region. The doping concentration of each region was adjusted with different doses of boron ion implantation. The fabricated LTTs showed good light triggering characteristics for a light pulse of 905 nm and a blocking voltage (VDRM) of 6,500 V. They drove an average on-state current (ITAVM) of 2,270 A, peak nonrepetitive surge current (ITSM) of 61 kA, critical rate of rise of on-state current (di/dt) of 1,010 A/㎲, and limiting load integral (I2T) of 17 MA2s without damage to the device.