• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
• /
• pp.546-549
• /
• 2009

In this paper, we investigated the effects of different source/drain (S/D) electrode materials in thin film transistors (TFTs) based on indium-gallium-zinc oxide (IGZO) semiconductor. A transfer length and effective resistances between S/D electrodes and amorphous IGZO thin-film transistors were examined. Intrinsic TFT parameters were extracted by the transmission line method (TLM) using a series of TFTs with different channel lengths measured at a low drain voltage. The TFTs fabricated with Cu S/D electrodes showed the lowest contact resistance and transfer length indicating good ohmic characteristics, and good transfer characteristics with a field-effect mobility (${\mu}_{FE}$) of 10.0 $cm^2$/Vs.

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2013년도 추계학술대회
• /
• pp.390-392
• /
• 2013

본 논문에서는 투명디스플레이를 구현하기 위해 가장 주목받는 ZnO 계열의 산화물반도체의 특성에 대하여 관찰하였다. 알에프 마그네트론 스퍼터링에 의해 증착된 산화물 반도체의 광학적 특성으로부터 전기적인 신호 동작특성의 상호관계를 알아보았다. 박막내의 결합 혹은 불순물이 증가할수록 PL 특성은 장파장 특성이 우세하게 나타났다. SiOC 박막위에서는 에너지 밴드갭이 증가하면서 단파장 특성이 우세하게 나타났다. 트랜지스터의 특성은 기판의 의존도가 높게 나타났다.

• Transactions on Electrical and Electronic Materials
• /
• 제15권6호
• /
• pp.328-332
• /
• 2014

Thin film transistors (TFTs) with an amorphous silicon zinc tin oxide (a-2SZTO) channel layer have been fabricated using an RF magnetron sputtering system. The effect of the change of excitation electron on the variation of the total interfacial trap states of a-2SZTO systems was investigated depending on sputtering power, since the interfacial state could be changed by changing sputtering power. It is well known that Si can effectively reduce the generation of the oxygen vacancies. However, The a-2SZTO systems of ZTO doped with 2 wt% Si could be degraded because the Si peripheral electron belonging to a p-orbital affects the amorphous zinc tin oxide (a-ZTO) TFTs of the s-orbital overlap structure. We fabricated amorphous 2 wt% Si-doped ZnSnO (a-2SZTO) TFTs using an RF magnetron sputtering system. The a-2SZTO TFTs show an improvement of the electrical property with increasing power. The a-2SZTO TFTs fabricated at a power of 30 W showed many of the total interfacial trap states. The a-2SZTO TFTs at a power of 30 W showed poor electrical property. However, at 50 W power, the total interfacial trap states showed improvement. In addition, the improved total interfacial states affected the thermal stress of a-2SZTO TFTs. Therefore, a-2SZTO TFTs fabricated at 50 W power showed a relatively small shift of threshold voltage. Similarly, the activation energy of a-2SZTO TFTs fabricated at 50 W power exhibits a relatively large falling rate (0.0475 eV/V) with a relatively high activation energy, which means that the a-2SZTO TFTs fabricated at 50 W power has a relatively lower trap density than other power cases. As a result, the electrical characteristics of a-2SZTO TFTs fabricated at a sputtering power of 50 W are enhanced. The TFTs fabricated by rf sputter should be carefully optimized to provide better stability for a-2SZTO in terms of the sputtering power, which is closely related to the interfacial trap states.

• 한국전기전자재료학회논문지
• /
• 제28권11호
• /
• pp.683-689
• /
• 2015

For the formation of $N^+$ doping, the antimony ions are mainly used for the fabrication of a BJT (bipolar junction transistor), CMOS (complementary metal oxide semiconductor), FET (field effect transistor) and BiCMOS (bipolar and complementary metal oxide semiconductor) process integration. Antimony is a heavy element and has relatively a low diffusion coefficient in silicon. Therefore, antimony is preferred as a candidate of ultra shallow junction for n type doping instead of arsenic implantation. Three-dimensional (3D) profiles of antimony are also compared one another from different tilt angles and incident energies under same dimensional conditions. The diffusion effect of antimony showed ORD (oxygen retarded diffusion) after thermal oxidation process. The interfacial effect of a $SiO_2/Si$ is influenced antimony diffusion and showed segregation effects during the oxidation process. The surface sputtering effect of antimony must be considered due to its heavy mass in the case of low energy and high dose conditions. The range of antimony implanted in amorphous and crystalline silicon are compared each other and its data and profiles also showed and explained after thermal annealing under inert $N_2$ gas and dry oxidation.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2011년도 제40회 동계학술대회 초록집
• /
• pp.284-284
• /
• 2011

Recently, the increasing degree of device integration in the fabrication of Si semiconductor devices, etching processes of nano-scale materials and high aspect-ratio (HAR) structures become more important. Due to this reason, etch selectivity control during etching of HAR contact holes and trenches is very important. In this study, The etch selectivity and etch rate of TEOS oxide layer using ACL (amorphous carbon layer) mask are investigated various process parameters in CH2F2/C4F8/O2/Ar plasma during etching TEOS oxide layer using ArF/BARC/SiOx/ACL multilevel resist (MLR) structures. The deformation and etch characteristics of TEOS oxide layer using ACL hard mask was investigated in a dual-frequency superimposed capacitively coupled plasma (DFS-CCP) etcher by different fHF/ fLF combinations by varying the CH2F2/ C4F8 gas flow ratio plasmas. The etch characteristics were measured by on scanning electron microscopy (SEM) And X-ray photoelectron spectroscopy (XPS) analyses and Fourier transform infrared spectroscopy (FT-IR). A process window for very high selective etching of TEOS oxide using ACL mask could be determined by controlling the process parameters and in turn degree of polymerization. Mechanisms for high etch selectivity will discussed in detail.

• 한국재료학회지
• /
• 제27권5호
• /
• pp.242-247
• /
• 2017

ZnO film was prepared on a p-type Si wafer and then annealed at various temperatures in air and vacuum conditions to research the electrical properties and bonding structures during the annealing processes. ZnO film annealed in atmosphere formed a crystal structure owing to the suppression of oxygen vacancies: however, ZnO annealed in vacuum had an amorphous structure after annealing because of the increment of the content of oxygen vacancies. Schottky contact was observed for the ZnO annealed in an air. O 1s spectra with amorphous structure was found to have a value of 529 eV; that with a crystal structure was found to have a value of 531.5 eV. However, it was observed in these results that the correlation between the electronic characteristics and the bonding structures was weak.

• Transactions on Electrical and Electronic Materials
• /
• 제18권6호
• /
• pp.323-329
• /
• 2017

This reports the electrical behavior, bonding structure and Schottky contact of gallium-zinc-oxide (GZO) thin film annealed at $100{\sim}400^{\circ}C$. The mobility of GZO with high density of PL spectra and crystal structure was also increased because of the structural matching between GZO and Si substrate of a crystal structure. However, the GZO annealed at $200^{\circ}C$ with an amorphous structure had the highest mobility as a result of a band to band tunneling effect. The mobility of GZO treated at low annealing temperatures under $200^{\circ}C$ increased at the GZO with an amorphous structure, but that at high temperatures over $200^{\circ}C$ also increased when it was the GZO of a crystal structure. The mobility of GZO with a Schottky barrier (SB) was mostly increased because of the effect of surface currents as well as the additional internal potential difference.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
• /
• pp.640-643
• /
• 2007

The effect of plasma damage was investigated on amorphous gallium-indium-zinc oxide (a-GIZO) films and transistors. Ion-bombardment by plasma process affects to turn semiconductor to conductor materials and plasma radiation may degrade to transistor electrical properties. All damages are easily recovered with a $350^{\circ}C$ thermal annealing.

• 한국표면공학회지
• /
• 제56권2호
• /
• pp.160-168
• /
• 2023

Recently, investigation on metallization is a key for a stretchable display. Amorphous metal such as Ni and Zr based amorphous metal compounds are introduced for a suitable material with superelastic property under certain stress condition. However, Ni and Zr based amorphous metals have too high resistivity for a display device's interconnectors. In addition, these metals are not suitable for display process chemicals. Therefore, we choose an aluminum based amprhous metal Al-Mo as a interconnector of stretchable display. In this paper, Amorphous Forming Composition Range (AFCR) for Al-Mo alloys are calculated by Midema's model, which is between 0.1 and 0.25 molybdenum, as confirmed by X-ray diffraction (XRD). The elongation tests revealed that amorphous Al-20Mo alloy thin films exhibit superior stretchability compared to pure Al thin films, with significantly less increase in resistivity at a 10% strain. This excellent resistance to hillock formation in the Al20Mo alloy is attributed to the recessed diffusion of aluminum atoms in the amorphous phase, rather than in the crystalline phase, as well as stress distribution and relaxation in the aluminum alloy. Furthermore, according to the AES depth profile analysis, the amorphous Al-Mo alloys are completely compatible with existing etching processes. The alloys exhibit fast etch rates, with a reasonable oxide layer thickness of 10 nm, and there is no diffusion of oxides in the matrix. This compatibility with existing etching processes is an important advantage for the industrial production of stretchable displays.

• 한국전기전자재료학회논문지
• /
• 제30권7호
• /
• pp.437-440
• /
• 2017

We report on amorphous thin-film transistors (TFTs) with indium zinc oxide (IZO) channel layers that were fabricated via a solution process. We prepared the IZO semiconductor solution with 0.1 M indium nitrate hydrate and 0.1 M zinc acetate dehydrate as precursor solutions. The solution- processed IZO TFTs showed good performance: a field-effect mobility of $7.29cm^2/Vs$, a threshold voltage of 4.66 V, a subthreshold slope of 0.48 V/dec, and a current on-to-off ratio of $1.62{\times}10^5$. To investigate the static response of our solution-processed IZO TFTs, simple resistor load-type inverters were fabricated by connecting a $2-M{\Omega}$ resistor. Our IZOTFTbased N-MOS inverter performed well at operating voltage, and therefore, isa good candidate for advanced logic circuits and display backplane.