• Title/Summary/Keyword: Short-channel Effect

Search Result 246, Processing Time 0.025 seconds

Quantum transport of doped rough-edged graphene nanoribbons FET based on TB-NEGF method

  • K.L. Wong;M.W. Chuan;A. Hamzah;S. Rusli;N.E. Alias;S.M. Sultan;C.S. Lim;M.L.P. Tan
    • Advances in nano research
    • /
    • v.17 no.2
    • /
    • pp.137-147
    • /
    • 2024
  • Graphene nanoribbons (GNRs) are considered a promising alternative to graphene for future nanoelectronic applications. However, GNRs-based device modeling is still at an early stage. This research models the electronic properties of n-doped rough-edged 13-armchair graphene nanoribbons (13-AGNRs) and quantum transport properties of n-doped rough-edged 13-armchair graphene nanoribbon field-effect transistors (13-AGNRFETs) at different doping concentrations. Step-up and edge doping are used to incorporate doping within the nanostructure. The numerical real-space nearest-neighbour tight-binding (NNTB) method constructs the Hamiltonian operator matrix, which computes electronic properties, including the sub-band structure and bandgap. Quantum transport properties are subsequently computed using the self-consistent solution of the two-dimensional Poisson and Schrödinger equations within the non-equilibrium Green's function method. The finite difference method solves the Poisson equation, while the successive over-relaxation method speeds up the convergence process. Performance metrics of the device are then computed. The results show that highly doped, rough-edged 13-AGNRs exhibit a lower bandgap. Moreover, n-doped rough-edged 13-AGNRFETs with a channel of higher doping concentration have better gate control and are less affected by leakage current because they demonstrate a higher current ratio and lower off-current. Furthermore, highly n-doped rough-edged 13-AGNRFETs have better channel control and are less affected by the short channel effect due to the lower value of subthreshold swing and drain-induced barrier lowering. The inclusion of dopants enhances the on-current by introducing more charge carriers in the highly n-doped, rough-edged channel. This research highlights the importance of optimizing doping concentrations for enhancing GNRFET-based device performance, making them viable for applications in nanoelectronics.

Reduction of Source/Drain Series Resistance in Fin Channel MOSFETs Using Selective Oxidation Technique (선택적 산화 방식을 이용한 핀 채널 MOSFET의 소스/드레인 저항 감소 기법)

  • Cho, Young-Kyun
    • Journal of Convergence for Information Technology
    • /
    • v.11 no.7
    • /
    • pp.104-110
    • /
    • 2021
  • A novel selective oxidation process has been developed for low source/drain (S/D) series resistance of the fin channel metal oxide semiconductor field effect transistor (MOSFET). Using this technique, the selective oxidation fin-channel MOSFET (SoxFET) has the gate-all-around structure and gradually enhanced S/D extension regions. The SoxFET demonstrated over 70% reduction in S/D series resistance compared to the control device. Moreover, it was found that the SoxFET behaved better in performance, not only a higher drive current but also higher transconductances with suppressing subthreshold swing and drain induced barrier lowering (DIBL) characteristics, than the control device. The saturation current, threshold voltage, peak linear transconductance, peak saturation transconductance, subthreshold swing, and DIBL for the fabricated SoxFET are 305 ㎂/㎛, 0.33 V, 13.5 𝜇S, 76.4 𝜇S, 78 mV/dec, and 62 mV/V, respectively.

Dependence of Channel Doping Concentration on Drain Induced Barrier Lowering for Asymmetric Double Gate MOSFET (비대칭 이중게이트 MOSFET에 대한 DIBL의 채널도핑농도 의존성)

  • Jung, Hakkee
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.20 no.4
    • /
    • pp.805-810
    • /
    • 2016
  • The dependence of drain induced barrier lowering(DIBL) is analyzed for doping concentration in channel of asymmetric double gate(DG) MOSFET. The DIBL, the important short channel effect, is described as lowering of source barrier height by drain voltage. The analytical potential distribution is derived from Poisson's equation to analyze the DIBL, and the DIBL is observed according to top/bottom gate oxide thickness and bottom gate voltage as well as channel doping concentration. As a results, the DIBL is significantly influenced by channel doping concentration. DIBL is significantly increased by doping concentration if channel length becomes under 25 nm. The deviation of DIBL is increasing with increase of oxide thickness. Top and bottom gate oxide thicknesses have relation of an inverse proportion to sustain constant DIBL regardless channel doping concentration. We also know the deviation of DIBL for doping concentration is changed according to bottom gate voltage.

New Fabrication Process of Vertical-Type Organic TFTs for High-Current Drivers

  • Kudo, Kazuhiro;Nakamura, Masakazu
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 2009.10a
    • /
    • pp.307-309
    • /
    • 2009
  • We have fabricated vertical-type organic transistors (static induction transistors; SITs) with built-in nano-triode arrays formed in parallel by a colloidal-lithography technique. Using this technique, we could fabricate a microstructure in a lateral direction within a large-scale organic device without relying on photolithography. The organic transistor showed low operating voltages, high current output, and large transconductance.

  • PDF

Analog Predistortion High Power Amplifier Using Novel Low Memory Matching Topology

  • Kim, Jang-Heon;Woo, Young-Yun;Cha, Jeong-Hyeon;Hong, Sung-Chul;Kim, Il-Du;Moon, Jung-Hwan;Kim, Jung-Joon;Kim, Bum-Man
    • Journal of electromagnetic engineering and science
    • /
    • v.7 no.4
    • /
    • pp.147-153
    • /
    • 2007
  • This paper represents an analog predistortion linearizer for the high power amplifier with low memory effect. The high power amplifier is implemented using a 90-W peak envelope power(PEP) LDMOSFET at 2.14-GHz and an envelope short matching topology is applied at the active ports to minimize the memory effect. The analog predistortion circuit comprises the fundamental path and the cuber and quintic generating circuits, whose amplitudes and phases can be controlled independently. The predistortion circuit is tested for two-tone and wide-band code division multiple access(WCDMA) 4FA signals. For the WCDMA signal, the adjacent channel leakage ratios(ACLRs) at 5 MHz offset are improved by 12.4 dB at average output powers of 36 dBm and 42 dBm.

Relation of Freshwater Discharge and Salinity Distribution on Tidal Variation around the Yeomha Channel, Han River Estuary (한강하구 염하수로 주변의 조석변화에 따른 염분분포와 담수와의 상관관계)

  • Yoon, Byung-Il;Woo, Seung-Buhm
    • Journal of Korean Society of Coastal and Ocean Engineers
    • /
    • v.24 no.4
    • /
    • pp.269-276
    • /
    • 2012
  • Salinity distribution in estuary and tidal river is presented by many parameters including tidal forcing, river discharge and geographical effect. Understanding the characteristics of salinity structure is very important in the aspect of water-quality, ecological, and engineering viewpoint. Field measurement was carried out to study the distribution of salinity structure at 2 surface stations at Yeomha channel in the Han River estuary. The results of short- and long-term salinity change according to short and long tidal variability is investigated. For analyzing the axial salinity distribution at Yeomha channel, the salinity data from NFRDI is used in this study. The relationship between freshwater discharge and salinity distribution is represented through the nonlinear regression equation. The empirical equation for salt intrusion length scale, including tide, river discharge, and topographical effect is presented. As the comparison of empirical equation and existing data collected in study area, the characteristic of salt intrusion length and salinity distribution is changed by tide, fresh water, and geographical effect.

A Study On the Effects of Velocity Staur Velocity Saturation on the Mosfet Devices (CARRIER속도 포화가 MOSFET소자특성에 미치는 영향에 관한 연구)

  • Park, Young-June
    • The Transactions of the Korean Institute of Electrical Engineers
    • /
    • v.36 no.6
    • /
    • pp.424-429
    • /
    • 1987
  • It has been observed that the reduction rate of the inversion layer carrier mobility due to the increase of the longitudinal electric field(drain to source direction) decreases as the transverse electric field increases. The effects of this physicar phenomenon to the I-V characteristics of the short channel NMOSFET are studied. It is shown that these effects increase the drain Current in the saturatio region, which agrees with the genarally observed decrepancy between the experimental I-V charateristics and the I-V modeling which dose not include this physical phenomenon. Also it is shown that this effect becomes more important when the device channel length decreases and the device operates in the high electric field range.

  • PDF

A NUMERICAL STUDY ON FLOW AND STIRRING CHARACTERISTICS IN A MICROCHANNEL WITH PERIODIC ARRAY OF CROSS BAFFLES (엇갈림 배플 구조의 마이크로 채널 내 유동 및 혼합 특성에 관한 수치해석적 연구)

  • Heo, S.G.;Heo, Y.G.;Heo, H.S.;Suh, Y.K.
    • 한국전산유체공학회:학술대회논문집
    • /
    • 2006.10a
    • /
    • pp.159-162
    • /
    • 2006
  • In the microfluidics devices the most important thing is mixing efficiency of various fluids. In this study a newly designed mixer is proposed to enhance the mixing effect with the purpose to apply it to microchannel mixing in a short future. This design is composed of a channel with cross baffles periodically arranged on the both bottom and top surfaces of the channel. To obtain the flow patterns, the numerical computation was performed by using a commercial code, ANSYS CFX 10.0. To evaluate the mixing performance, we computed Lyapunov exponent and obtained Poincare sections.

  • PDF

Analysis of the Electrical Characteristics with Channel Length in n-ch and p-ch poly-Si TFT's (채널 길이에 따른 n-채널과 p-채널 Poly-Si TFT's의 전기적 특성 분석)

  • Back, Hee-Won;Lee, Jea-Huck;Lim, Dong-Gyu;Kim, Young-Ho
    • Proceedings of the KIEE Conference
    • /
    • 1999.11d
    • /
    • pp.971-973
    • /
    • 1999
  • 채널길이에 따른 n-채널과 p-채널 poly-Si TFT's를 제작하고 그 전기적 특성을 분석하였다. n-채널과 p-채널소자는 공통적으로 기생바이폴라트 랜지스터현상(parasitic bipolar transistor action)에 의한 kink 효과, 전하공유(charge sharing)에 의한 문턱전압의 감소, 소오스와 드레인 근처의 결함에 의한 RSCE(reverse short channel effect) 효과, 수직전계에 의한 이동도의 감소, 그리고 avalanche 증식에 의한 S-swing의 감소가 나타났다. n-채널은 p-채널 보다 더 큰 kink, 이동도, S-swing의 변화가 나타났으며, 높은 드레인 전압에서의 문턱전압의 이동은 avalanche 증식(multiplication)에 의한 것이 더 우세한 것으로 나타났다. 누설전류의 경우, 채널 길이가 짧아짐에 따라 n-채널은 큰 증가를 나타냈으나 p-채널의 경우는 변화가 나타나지 않았다.

  • PDF

Effect of Bundle Junction Face and Misalignment on the Pressure Drops Across a Randomly Loaded and Aligned 12 Bundles in Candu Fuel Channel

  • H. C. Suk;K. S. Sim;C. H. Chung;Lee, Y. O.
    • Nuclear Engineering and Technology
    • /
    • v.28 no.3
    • /
    • pp.280-289
    • /
    • 1996
  • The pressure drop of twelve fuel bundle string in the CANDU-6 fuel channel is equal to the sum of the eleven junction pressure losses, the bundle string entrance and exit pressure losses, the skin friction pressure loss, and other appendage pressure losses, where the junction loss is dependent on the bundle end faces and angular alignments of the junctions. The results of the single junction pressure drop tests in a short rig show that the most probable pressure drop of the eleven junctions was analytically equal to the eleven times of average pressure drop of all the possible single junction pressure drops, and also that the largest and smallest junction pressure drops across the eleven junctions probably occurred only with BA and BB type junctions, respectively, where A and B denote the bundle end sides with an end-plates on which a company monogram is stamped and unstamped, respectively.

  • PDF