• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.9
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• pp.551-554
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• 2014

This paper was showed latch up characteristics of super junction power MOSFET by parasitic thyristor according to trench etch angle. As a result of research, if trench etch angle of super junction MOSFET is larger, we obtained large latch up voltage. When trench etch angle was $90^{\circ}$, latch up voltage was more 50 V. and we got 700 V breakdown voltage. But we analyzed on resistance. if trench etch angle of super junction MOSFET is larger, we obtained high on resistance. Therefore, we need optimal point by simulation and experiment for solution of trade off.

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.3
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• pp.263-267
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• 2014

Super junction trench gate power MOSFETs have been receiving attention in terms of the trade-off between breakdown voltage and on-resistance. The vertical structure of super junction trench gate power MOSFETs allows the on-resistance to be reduced compared with conventional Trench Gate Power MOSFETs. The heat release of devices is also decreased with the reduction of on-resistance. In this paper, Lattice Temperature of two devices, Trench Gate Power MOSFET and Super junction trench gate power MOSFET, are compared in several temperature circumstance with the same Breakdown Voltage and Cell-pitch. The devices were designed by 100V Breakdown voltage and measured from 250K Lattice Temperature. We have tried to investigate how much temperature rise in the same condition. According as temperature gap between top of devices and bottom of devices, Super junction trench gate power MOSFET has a tendency to generate lower heat release than Trench Gate Power MOSFET. This means that Super junction trench gate power MOSFET is superior for wide-temperature range operation. When trench etching process is applied for making P-pillar region, trench angle factor is also important component. Depending on trench angle, characteristics of Super junction device are changed. In this paper, we focus temperature characteristic as changing trench angle factor. Consequently, Trench angle factor don't have a great effect on temperature change.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.5
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• pp.403-409
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• 2007

In this paper, effects of the trench angle($\theta$) on the breakdown voltage according to the process parameters of p-base region and doping concentrations of n-drift region in a Trench Gate IGBT (TIGBT) device were analyzed by computer simulation. Processes parameters used by variables are diffusion temperature, implant dose of p-base region and doping concentration of n-drift region, and aspects of breakdown voltage change with change of each parameter were examined. As diffusion temperature of the p-base region increases, depth of the p-base region increases and effect of the diffusion temperature on the breakdown voltage is very low in the case of small trench angle($45\;^{\circ}$) but that is increases 134.8 % in the case of high trench angle($90\;^{\circ}$). Moreover, as implant dose of the p-base region increases, doping concentration of the p-base region increases and effect of the implant dose on the breakdown voltage is very low in the case of small trench angle($45\;^{\circ}$) but that is increases 232.1 % in the case of high trench angle($90\;^{\circ}$). These phenomenons is why electric field concentrated in the trench is distributed to the p-base region as the diffusion temperature and implant dose of the p-base increase. However, effect of the doping concentration variation in the n-drift region on the breakdown voltage varies just 9.3 % as trench angle increases from $45\;^{\circ}$ to $90\;^{\circ}$. This is why magnitude of electric field concentrated in the trench changes, but direction of that doesn't change. In this paper, respective reasons were analyzed through the electric field concentration analysis by computer simulation.

• Journal of IKEEE
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• v.18 no.4
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• pp.532-535
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• 2014

This paper analyzed thermal characteristics of super junction MOSFET using process and design parameters. Trench process is very important to super junction MOSFET process. We analyzed the difference of temperature, thermal resistance, total power consumption according to trench etch angle. As a result we obtained minimum value of temperature difference and thermal resistance at $89.3^{\circ}$ of trench etch angle. The electrical characteristics distribution of super junction MOSFET is not showed tendency according to trench etch angle. We need iterative experiments and simulation for optimal value of electrical characteristics. The super junction power MOSFET that has superior thermal characteristics will use automobile and industry.

• Journal of Electrical Engineering and Technology
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• v.9 no.3
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• pp.843-847
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• 2014

In Super Junction (SJ) MOSFETs, charge balance is the most important issue of the SJ fabrication process. In order to achieve the best electrical characteristics, such as breakdown voltage and on-resistance, the N-type and P-type drift regions must be fully depleted when the drain bias approaches the breakdown voltage, which is known as the charge balance condition. In conventional charge balance analysis, based on multi-epi process SJ MOSFETs, analytical model has only N, P pillar width and doping concentration parameter. But applying a conventional charge balance principle to trench filling process, easier than Multi-epi process, is impossible due to the missing of the trench angle parameter. To achieve much more superior characteristics of on-resistance in trench filling SJ MOFET, the appropriate trench angle is necessary. So in this paper, modulated charge balance analysis is proposed, in which a trench angle parameter is added. The proposed method is validated using the TCAD simulation tool.

• Journal of Electrical Engineering and Technology
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• v.9 no.3
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• pp.964-969
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• 2014

In Super Junction MOSFET, Charge Balance is the most important issue of the trench filling Super Junction fabrication process. In order to achieve the best electrical characteristics, the N type and P type drift regions must be fully depleted when the drain bias approaches the breakdown voltage, called Charge Balance Condition. In this paper, two methods from the fabrication process were used at the Charge Balance condition: Trench angle decreasing process and Bottom implantation process. A lower on-resistance could be achieved using a lower trench angle. And a higher breakdown voltage could be achieved using the bottom implantation process. The electrical characteristics of manufactured discrete device chips are compared with those of the devices which are designed of TCAD simulation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.8
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• pp.497-500
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• 2014

In this paper, we analyze electrical characteristics of n/p-pillar layer according to trench angle which is the most important characteristics of SJ MOSFET and core process. Because research target is 600 V class SJ MOSFET, so conclusively trench angle deduced 89.5 degree to implement the breakdown voltage 750 V with 30% margin rate. we found that on resistance is $22mohm{\cdot}cm^2$ and threshold voltage is 3.5 V. Moreover, depletion layer of electric field distribution also uniformly distributes.

• Journal of the Korean Institute of Gas
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• v.21 no.1
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• pp.27-33
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• 2017

In this study, the stability of trench slope was analysed in summer and winter seasons for the construction of pipelines in permafrost regions. The construction standards of Korea, Russia and UK were compared for obtaining an optimum trench shape for a pipeline of 30 in. diameter. Using the geotechnical properties of soil in Yakutsk (Russia), the stability of trench slope was analysed using Strength Reduction Method (SRM) according to the horizontal slope angle values of $0^{\circ}$, $10^{\circ}$, $20^{\circ}$ and $30^{\circ}$ and vertical slope angle values of $20^{\circ}$, $30^{\circ}$ and $40^{\circ}$. In both seasons, an increase in the slope angle results in a decrease in the factor of safety. The results show that horizontal slope angle of $30^{\circ}$ was not safe in summer season. At the vertical slope angle of $20^{\circ}$, trench side failure was observed, whereas, ground slope failure was observed at the vertical slope angles of $30^{\circ}$ and $40^{\circ}$. Due to the solidification of pore water at temperatures below $0^{\circ}C$, cementation of soil particles take place. Therefore, the trench slope was found to be stable in the winter season at all vertical and horizontal slop angles, except for special load cases and abrupt temperature changes.

• Journal of the Korean Vacuum Society
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• v.6 no.3
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• pp.267-274
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• 1997

Silicon shallow trenches applied to the STI (Shallow Trench Isolation) of integrated circuits were etched using inductively coupled $Cl_2$ and HBr/$Cl_2$ plasmas and the effects of process parameters on the etch profiles of silicon trenches and the physical damages on the trench sidewall and bottom were investigated. The increase of inductive power and bias voltage in $Cl_2$ and HBr/$Cl_2$ plasmas increased polysilicon etch rates in general, but reduced the etch selectivities over nitride. In case of $Cl_2$ plasma, low inductive power and high bias voltage showed an anisotropic trench etch profile, and also the addition of oxygen or nitrogen to chlorine increased the etch anisotropy. The use of pure HBr showed a positively angled etch profile and the addition of $Cl_2$ to HBr improved the etch profile more anisotropically. HRTEM study showed physical defects formed on the silicon trench surfaces etched in $Cl_2/N_2$ or HBr/ $Cl_2$ plasmas.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.8
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• pp.501-504
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• 2014

This paper was developed and described core-process to implement low on resistance which was the most important characteristics of SJ (super junction) MOSFET. Firstly, using process-simulation, SJ MOSFET optimal structure was set and developed its process flow chart by repeated simulation. Following process flow, gate level process was performed. And source and drain level process was similar to genral planar MOSFET, so the process was the same as the general planar MOSFET. And then to develop deep trench process which was main process of the whole process, after finishing photo mask process, we developed deep trench process. We expected that developed process was necessary to develop SJ MOSFET for automobile semiconductor.