• 전자공학회논문지D
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• 제35D권8호
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• pp.8-14
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• 1998

A new process is developed to improve the electrical characteristics of high .beta. and low saturation voltage power transistor for lamp solenoid driver application. To prevent punch-through breakdown, appropriate combination of base doping and base width is necessary in the range of operating voltage of the circuit. The optimum values of base doping and sheet resistance are $Q_{D}$= $1.5{\times}10^{14}$atoms/$\textrm{cm}^2$ and $R_{s}$= 350 $\Omega/\square$ base wodtj $W_{B}$= $2.5{\mu}m$respectively. Under this condition it is possible to control $\beta$ of the transistor to 1500, maintaining $VB_{CBO}$ =200V. To reduce scattered distribution of .beta. of the devices on the wafer, it is necessary to improve emittter predeposition process. As a result, scattered distribution of .beta. of the devices on the wafer was reduced to 1/6 by using the new process. To improve collector to emitter forward voltage drop, $V_{ECF}$ of damper diode, an additional silicon etching process is used, which resulted in improving the value of $V_{eCF}$ from 2.8 V to 1.8V. With the suggested process superior device performance and higher yield are achieved.

• KIEE International Transactions on Electrophysics and Applications
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• 제4C권3호
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• pp.111-116
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• 2004

The Ni/SiC Schottky diode was fabricated with the $\alpha$-SiC thin film grown by the ICP-CVD method on a (111) Si wafer. $\alpha$-SiC film has been grown on a carbonized Si layer in which the Si surface was chemically converted to a very thin SiC layer achieved using an ICP-CVD method at $700^{\circ}C$. To reduce defects between the Si and $\alpha$-SiC, the surface of the Si wafer was slightly carbonized. The film characteristics of $\alpha$-SiC were investigated by employing TEM (Transmission Electron Microscopy) and FT-IR (Fourier Transform Infrared Spectroscopy). Sputterd Ni thin film was used as the anode metal. The boundary status of the Ni/SiC contact was investigated by AES (Auger Electron Spectroscopy) as a function of the annealing temperature. It is shown that the ohmic contact could be acquired beyond a 100$0^{\circ}C$ annealing temperature. The forward voltage drop at 100A/cm was I.0V. The breakdown voltage of the Ni/$\alpha$-SiC Schottky diode was 545 V, which is five times larger than the ideal breakdown voltage of the silicon device. As well, the dependence of barrier height on temperature was observed. The barrier height from C- V characteristics was higher than those from I-V.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.288-291
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• 2004

Due to the charge compensation effect, SOI(Silicon-On-Insulator) LIGBT with dual-epi layer have been found to exhibit both low forward voltage drop and high static breakdown voltage. In this paper, electrical characteristics of the SOI LIGBT with dual-epi structure is presented. Trenched anode structure is employed to obtain uniform current flowlines and shorted anode structure also employed to prevent the fast latch-up. Latching current density of the proposed LIGBT with $T_1=T_2=2.5{\mu}m,\;N_1=7{\times}10^{15}/cm^3,\;N_2=3{\times}10^{15}/cm^3$ is $800A/cm^2$ and breakdown voltage is 125V while latching current density and breakdown voltage of the conventional LIGBT is $700A/cm^2$ and 55V.

• 전기전자학회논문지
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• 제11권4호
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• pp.158-164
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• 2007

본 논문에서는 전력용 스위칭 소자로 널리 활용되고 있는 IGBT 소자 중 수평 게이트 구조보다 우수한 특성을 지닌 트렌치 게이트 IGBT(TIGBT) 구조를 채택하여, 기존의 TIGBT가 갖는 구조적 한계를 극복하고 좀 더 우수한 전기적 특성을 갖는 새로운 구조의 수직형 TIGBT를 제안하였다. 첫 번째로 제안한 IGBT 소자는 P+컬렉터를 산화막으로 고립시킴으로서 N-드리프트 층으로의 정공 주입효율을 극대화하여 기존 구조보다 더 낮은 순방향 전압강하를 얻도록 설계된 구조이다. 두 번째 제안한 구조는 양 게이트 사이의 P-베이스 구조를 볼록하게 형성함으로서 게이트 쪽으로 집중되는 전계의 일부를 접합부 쪽으로 유도하여 기존 구조보다 더 높은 항복전압을 얻을 수 있다. 또한 P-베이스의 볼록한 구조가 턴-오프 시 정공의 흐름을 개선시켜 기존 구조보다 더 빠른 턴-오프 시간을 갖게 된다. 시뮬레이션 결과 첫 번째 구조의 특징은 2.4V의 순방향 전압강하 특성을 갖는 기존의 IGBT 구조보다 상당히 낮은 2.1V의 순방향 전압강하 특성을 나타냈으며, 두 번째 구조는 기존의 IGBT 보다 10V정도 높아진 항복전압 특성을 보였다. 또한 두 번째 구조에서 기존 구조와 비교해볼 때 9ns 정도 빠른 턴-오프 시간을 보였다. 최종적으로 제안된 새로운 구조의 TIGBT는 위 두 구조가 갖는 우수한 전기적 특성을 모두 갖도록 결합한 것이며, 시뮬레이션 결과 기본의 TIGBT 소자보다 순방향 전압강하, 항복특성, 그리고 턴 오프 특성이 모두 우수한 결과를 나타냈다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.967_968
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• 2009

For lighting application, high-power LED nowadays is driven at 350mA and a sensing resistor is used to provide feedback for LED-current regulation. This method adds an IR drop at the output branch, and limits power efficiency as LED current is large and keeps increasing. In this paper, a power efficient LED-current sensing circuit is proposed. The circuit does not use any sensing resistor but extracts LED-current information from the output capacitor of the driver. Controlling the brightness of LEDs requires a driver that provides a constant, regulated current. In one case, the converter may need to step down the input voltage, and, in another, it may need to boost up the output voltage. These situations often arise in applications with wide-ranging ""dirty"" input power sources, such as automotive systems. And, the driver topology must be able to generate a large enough output voltage to forward bias the LEDs. So, to provide this requirements, 13W prototype Buck-Boost Converter is used.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 C
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• pp.932-934
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• 1999

In this paper, the new IGBT structures with trap injection are proposed to improve switching characteristics of the conventional SOI LIGBT. The simulations are used in order to investigate the effects of the position, width and concentration of trap injection region using 2D device simulator MEDICI. And, their electrical characteristics are analyze and the optimum design parameters are extracted. As a result of simulation, the turn off time for the proposed LIGBT model A by the trap injection is $0.78{\mu}s$. And, the latch up voltage is 3.4V and forward blocking voltage is 168V which are superior to that of conventional structure. In addition, the proposed model is achieved more efficient in switching time and process effort. Therefore, It is shown that the trap injection is very effective to reduce the turn off time with a little increasing of on-state voltage drop if its design and process parameters are optimized.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.67-68
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• 2008

In this study we have developed a packaged silicon carbide power diode with blocking voltage of 2kV. PiN diodes with 7 field limiting rings (FLRs) as an edge termination were fabricated on a 4H-SiC wafer with $30{\mu}m$-thick n-epilayer with donor concentration of $1.6\times10^{15}cm^{-3}$. From packaged PiN diode testing, we obtained reverse blocking voltage of 2kV, forward voltage drop of 4.35V at 100A/$cm^2$, on-resistance of $6.6m{\Omega}cm^2$, and about 8 nanosec reverse recovery time. These properties give a potential for the power system application.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권3호
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• pp.161-166
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• 1999

We investigate the device characteristics of the separated shorted-anode LIGBT (SSA-LIGBT), which suppresses effectively the negative differential resistance regime, by 2-dimensional numerical simulation. The SSA-LIGBT increases the pinch resistance by employing the highly resistive n-drift region as an electron conduction path instead of the lowly resistive n buffer region of the conventional SA-LIGBT. The negative differential resistance regime of the SSA-LIGBT is significantly suppressed as compared with that of the conventional SA-LIGBT. The SSA-LIGBT shows the lower forward voltage drop than that of the conventional SA-LIGBT.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.387-392
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• 2018

Static characteristics of SiC (silicon carbide) lateral p-i-n diodes implemented on semi-insulating substrate without an epitaxial layer are inVestigated. On-axis SiC HPSI (high purity semi-insulating) and VDSI (Vanadium doped semi-insulating) substrates are used to fabricate the lateral p-i-n diode. The space between anode and cathode ($L_{AC}$) is Varied from 5 to $20{\mu}m$ to inVestigate the effect of intrinsic-region length on static characteristics. Maximum breakdown Voltages of HPSI and VDSI are 1117 and 841 V at $L_{AC}=20{\mu}m$, respectiVely. Due to the doped Vanadium ions in VDSI substrate, diffusion length of carriers in the VDSI substrate is less than that of the HPSI substrate. A forward Voltage drop of the diode implemented on VDSI substrate is 12 V at the forward current of $1{\mu}A$, which is higher than 2.5 V of the diode implemented on HPSI substrate.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권3호
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• pp.165-168
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• 2000

Improvement on the switching characteristic of IGBT by means of the uniform and local lifetime control is studied numerically using two-dimensional simulator, MEDICI. In the case of uniform lifetime control, the on-state and switching characteristics are simulated as a function of lifetime, and compared with the experimental results reported, which allows a relationship between dose of electron irradiation and controlled lifetime. In the case of local lifetime control, simulations are carried out by varying the position, width, and lifetime of the locally controlled region, and the results are compared with the characteristics for the case of the uniform lifetime control. The turn-off time of the device with an optimized locally controlled region is found to decrease from about $4.5\mus$ to 0.11$mutextrm{s}$ while the forward voltage drop increases from 1.37V to 2.61V in comparison with that for the uniform lifetime control.