• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.151-151
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• 2010

In this paper, the electrically properties of nonvolatile memory (NVM) using multi-stacks gate insulators of oxide-nitride-oxynitride (ONOn) and active layer of the low temperature polycrystalline silicon (LTPS) were investigated. From hydrogenated amorphous silicon (a-Si:H), the LTPS thin films with high crystalline fraction of 96% and low surface's roughness of 1.28 nm were fabricated by the metal induced crystallization (MIC) with annealing conditions of $650^{\circ}C$ for 5 hours on glass substrates. The LTPS thin film transistor (TFT) or the NVM obtains a field effect mobility of ($\mu_{FE}$) $10\;cm^2/V{\cdot}s$, threshold voltage ($V_{TH}$) of -3.5V. The results demonstrated that the NVM has a memory window of 1.6 V with a programming and erasing (P/E) voltage of -14 V and 14 V in 1 ms. Moreover, retention properties of the memory was determined exceed 80% after 10 years. Therefore, the LTPS fabricated by the MIC became a potential material for NVM application which employed for the system integration of the panel display.

• 대한전자공학회논문지SD
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• 제43권10호
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• pp.61-67
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• 2006

본 논문에서는 Poly-Si의 불규칙한 Grain boundary 분포로 인해 발생하는 문턱전압의 변화에 대해서도 일정한 전류를 흘려줄 수 있는 전류원을 제안하였다. 기존의 문턱전압 보상 전류원에 비해 넓은 입력전압 범위에서도 포화영역의 특성이 매우 향상되었으며 문턱전압의 변화에 따른 전류의 오차를 감소시킬 수 있었다. 마지막으로 HSPICE 시뮬레이션 과정을 통해 Poly-Si TFT의 특성곡선과 제안된 전류원의 특성곡선을 비교하였으며 각각의 입력전압에 대한 문턱전압의 변화에 따른 출력전류의 상대오차를 측정하였다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.8-11
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• 2007

The new technologies in mobile display developed in SEC are briefly reviewed. For a differentiation, SEC's LTPS line is based on SLS (Sequential Lateral Solidification) technology. In this paper, the characteristics of SEC's SLS in recent and future mobile displays were discussed. The microstructure produced by SLS crystallization is dependent on SLS process conditions such as mask design, laser energy density, and pulse duration time. The microstructure and TFT (Thin Film Transistor) performance are closely related. For an optimization of TFT performance, SLS process condition should be adjusted. Other fabrication processes except crystallization such as blocking layer, gate insulator deposition and cleaning also affect TFT performance. Optimized process condition and tailoring mask design can make it possible to produce high quality AMOLED devices. The TFT non-uniformity caused by laser energy density fluctuation could be successfully diminished by mixing technology.

• Journal of Information Display
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• 제6권4호
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• pp.11-15
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• 2005

We propose a current mode logic circuit design method for LTPS TFT for enhancing circuit operating speed. Current mode inverter/buffers with passive resistive load had been designed and fabricated. Measurement results indicated that the smaller logic swing of the current mode allowed significantly faster operation than the static CMOS. In order to reduce the chip size, both all pTFT and all nTFT active load current mode inverter/buffer had been designed and analyzed by HSPICE simulation. Even though the active load current mode circuits were inferior to the passive load circuits, it was superior to static CMOS gates.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.446-449
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• 2004

We developed a dynamic logic architecture which resulted better leakage current, lower power consumption and less area compared to the conventional dynamic logic structures. We demonstrated the advantage from HSPICE simulation and test chip design has been completed.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.119-123
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• 2004

This paper describes low temperature poly-Si (LTPS) TFT system on glass (SOG) technology developed in NEC. High resolution SOG-LCDs such as a 230 ppi reflective type LCD, a 2.5", 333 ppi 2D/3D autostereoscopic LCD, and a 2.1" single voltage driven full integration LCD for mobile applications and a 0.9", XGA light valve for projectors are reviewed from the perspective of the high resolution technologies

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.630-633
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• 2003

Integrating the driver circuitry directly onto the glass substrate would be one of the advantages of polycrystalline Si (poly-Si) TFT-(LCD). Low-temperature poly-Si TFT(LTPS) is well-suited for higher-definition display applications due to its intrinsically superior electrical characteristics. In order to improve LTPS electrical characteristics, currently the excimer laser-induced crystallization (ELC) processes and sequential lateral solidification method were developed. Grain size of the poly-Si is mainly affected by beam pitch and energy density. Key parameter for making a larger poly-Si using excimer laser annealing(ELA) and increasing a throughput is due to increase in beam pitch and energy density to a certain degree. Furthermore, thin $SiO_{2}$ capping is effective to suppress the protrusion of the poly-Si thin films and to reduce the interface state density. From the ELA process, we are able to control grain size by varying different parameters such as number of shots and energy density.

• 대한전자공학회논문지SD
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• 제44권2호
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• pp.104-112
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• 2007

본 논문에서는 저온 다결정 실리콘 공정에서 얻어지는 박막트랜지스터를 이용하여 $7{\times}7$ 병렬처리 곱셈기를 설계하였다. 7개의 부분곱은 Folding 회로를 기본으로 설계된 다치 논리 회로(7-3 Compressor)와 3-2 Compressor를 통해 2비트로 출력되어 Carry Propagating Adder로 전달되는 구조를 통해 Carry전달 지연을 최소화하여 연산속도를 향상시켰다. 그리고 전류모드로 동작하는 곱셈기에서 사용되는 전류원을 부분적으로 차단함으로써 전력소모를 감소시켰다. HSPICE 시뮬레이션 과정을 통해 제안된 곱셈기는 Wallace Tree 곱셈기에 비해 PDP(Power Delay Product)가 23%, EDP(Energy Delay Product)가 59%, 연산 속도가 47% 향상됨을 확인하였다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
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• pp.1075-1078
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• 2007

Negative Bias Temperature Instability (NBTI) in Eximer Laser Annealing (ELA) based Low Temperature polysilicon (LTPS) Thin-Film Transistors (TFT) was investigated. Even though NBTI is generally appeared in devices with thin gate oxide, the TFT with gate oxide thickness of 120 nm, relatively thick, also showed NBTI effect and dynamic NBTI effect is dependent on operational frequency.

• Journal of Information Display
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• 제11권1호
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• pp.12-16
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• 2010

The effect of the crystallization and activated annealing of Si films using an excimer laser and the new CW blue laser are described and compared with furnace annealing for application in advanced TFTs and for future applications. Pulsed excimer laser annealing (ELA) is currently being used extensively as a low-temperature poly-silicon (LTPS) process on glass substrates as its efficiency is high in the ultra-violet (UV) region for thin Si films with thickness of 40-60 nm. ELA enables extremely low resistivity relating to high crystallinity for both the n- and p-type Si films. On the other hand, CW blue laser diode annealing (BLDA) enables the smooth Si surface to have arbitral crystal grains from micro-grains to an anisotropic huge grain structure only by controlling its power density. Both annealing techniques are expected to be applied in the future advanced TFT systems.