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收集所有交通大學研究人員與學生個人或團體所發表之各項學術著作,涵蓋期刊論文、教師專書、學位論文等項。;;Collections of Publications of NCTU Researchers and Students Like Journal Papers and Thesis.

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  • Item type:Item,
    Performance Impacts of Analog ReRAM Non-ideality on Neuromorphic Computing
    (2019-03-01)
    Lin, Yu-Hsuan
    ;
    Wang, Chao-Hung
    ;
    Lee, Ming-Hsiu
    ;
    Lee, Dai-Ying
    ;
    Lin, Yu-Yu
    Resistive random access memory (ReRAM) is often considered as a strong candidate for storing the weights in non-von Neumann neuromorphic computing systems. This paper studies how nonideal memory characteristics, which include programing error, read fluctuation, and retention, affect the inference accuracy of the analog ReRAM neural networks by incorporating memory characteristics extracted from 1-Mb ReRAM into a simulated inference-only neural network. This paper also shows that the different layer in the network can tolerate different amount of such imperfects. We learned four key points: 1) the conductance range of memory with less relative fluctuation is preferred for designing the weight-conductance mapping; 2) the control of programing error is essential for high inference accuracy; 3) retention-induced conductance drift can be fatal to the neuromorphic system. A compensation scheme is proposed in this paper which can effectively recover the inference accuracy; and 4) for multilayer networks, avoiding weight errors in the front layers can help to maintain the inference accuracy by reducing calculation error which may otherwise accumulate and pass down the networks. The concepts and approaches of this paper can also be applied to evaluate other types of nonvolatile memories for artificial neural networks.
  • Item type:Item,
    MULTI-LEVEL OPERATION OF FULLY CMOS COMPATIBLE WOX RESISTIVE RANDOM ACCESS MEMORY (RRAM)
    (2009)
    Chien, W. C.
    ;
    Chen, Y. C.
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    Chang, K. P.
    ;
    Lai, E. K.
    ;
    Yao, Y. D.
    The multi-level operation of WOX based RRAM has been investigated. Improvement of our WOX process has produced an extended linear R-V region for our devices. By adding an electrical forming process and a program-verify algorithm we have demonstrated stable 2-bit/cell operation, with potential for 3-bit/cell. The reliability of the MLC operation has been examined and very stable high temperature retention, robust read disturb immunity and initial cycling endurance of >1,000 times have been demonstrated.
  • Item type:Item,
    A Study of Blocking and Tunnel Oxide Engineering on Double-Trapping (DT) BE-SONOS Performance
    (2015)
    Lo, Roger
    ;
    Du, Pei-Ying
    ;
    Hsu, Tzu-Hsuan
    ;
    Wu, Chen-Jun
    ;
    Guo, Jung-Yi
    Double-trapping bandgap engineered SONOS (DT BE-SONOS) [1] was proposed to provide both fast erase speed and deep erase by means of a second nitride trapping layer and an additional blocking oxide on top of BE-SONOS. Although this provides excellent erase performance but the additional layers increase the EOT and subsequently the erase voltage, thus it is desirable to minimize their impact. This work investigates exhaustively the effect of thinning down the blocking layers. Since the ISPP and high temperature retention charge loss are mainly dominated by the ONO thickness of BE-SONOS below the blocking layers, reducing the blocking layer thickness has only minor impact on ISPP and retention. Moreover, erase saturation is determined by the dynamic balance of channel hole injection and gate electron injection. Experimental data show that reducing the thickness of the oxide between two trapping layers has little impact on erase saturation once the gate injected electrons are efficiently suppressed by the top most oxide. We have also investigated retention improvement by various oxides. By using HQ-SiO2 to replace the top tunnel ONO the trapped electron out-tunneling is reduced. Thus retention may be improved without increasing the effective oxide thickness.