Browsing by Author "Lee, DY"

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Breakdown modes and their evolution in ultrathin gate oxide
(2002-10-01)
Lin, HC
;
Lee, DY
;
Huang, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Post-breakdown current-voltage characteristics of metal-oxide-semiconductor (MOS) devices kith an ultrathin gate oxide layer have been carefully studied. Several breakdown modes were identified. Specifically, it was found that the typical soft-breakdown mode induced in an oxide lay er thinner than 3 nm is actually quite different from that in an oxide layer thicker than 3 nm. Based on these findings, we have also proposed a model to explain the evolution of different breakdown modes. The model takes into consideration the thermal runaway process at the breakdown moment, and is substantiated by a number of experimental findings. Impacts of each breakdown mode on device switching behavior are also discussed.
Effects of process and gate doping species on negative-bias-temperature instability of p-channel MOSFETs
(2004-02-01)
Lee, DY
;
Huang, TY
;
Lin, HC
;
Chiang, WJ
;
Huang, GW
The effects of poly-Si gate doping type and species as well as thermal treatments on negative-bias-temperature instability (NBTI) of p-channel metal-oxide-semiconductor field effect transistors (MOSFETs) were investigated. We found that devices with n(+)-poly-Si gate depict a smaller threshold voltage shift after bias-temperature stressing, compared to their p(+)-poly-Si-gated counterparts. By carefully controlling the thermal budget to suppress boron penetration, NBTI can be reduced by fluorine incorporation in p(+)-poly-Si-gated devices. Finally, NBTI is found to be aggravated in devices subjected to H-2 postmetal-annealing, highlighting the important role of hydrogen bonds. (C) 2004 The Electrochemical Society.
Enhanced negative-bias-temperature instability of P-channel metal-oxide-semiconductor transistors due to plasma charging damage
(2002-04-01)
Lee, DY
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Lin, HC
;
Wang, MF
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Tsai, MY
;
Huang, TY
The effects of plasma charging on the negative-bias-temperature instability (NBTI) of p-channel metal-oxide-semiconductor (PMOS) transistors were explored in this work. It is clearly shown that the threshold voltage shift during bias-temperature stressing (BTS) could be enhanced by plasma charging damage. More importantly, we also found that electron trappings are aggravated by plasma charging, even on new devices with large antenna area ratios prior to BTS. Our charge pumping current measurements confirm that the interface-state density is increased for devices with large antennas, both before and after the BTS. This indicates, without ambiguity, that electron trapping is solely responsible for the observed low (in absolute value) threshold voltage in new devices with large antennas. Finally, it is proposed that the NBTI characterization can be used as a sensitive method for characterizing the antenna effects in devices with ultrathin gate oxide, which is particularly attractive in light of the fact that conventional indicators are becoming inadequate as oxide is scaled down.
Impacts of HF etching on ultra-thin core gate oxide integrity in dual gate oxide CMOS technology
(2003)
Lee, DY
;
Lin, HC
;
Chen, CL
;
Huang, TY
;
Wang, TH
In this paper, we investigate the effects of HF etching on the integrity of ultra-thin oxides in dual gate oxide (DGO) CMOS technologies. We found that both the BF concentration in the etching solution and the over etching (OE) time are important parameters that greatly affect the device performance and reliability. Our results indicate that, with a proper over etching period, using a heavy BF solution results in better ultra-thin gate oxides in terms of reduced defect density, improved device performance and reliability, compared to using diluted BF solution. It is also found for the first time that negative-bias-temperature instability (NBTI) immunity for PMOSFETs is improved by using heavy HF solution.
Post-soft-breakdown characteristics of deep submicron NMOSFETs with ultrathin gate oxide
(2001-07-01)
Tsai, MY
;
Lin, HC
;
Lee, DY
;
Huang, TY
;
電子工程學系及電子研究所
The impacts of soft-breakdown (SBD) on the characteristics of deep sub-micron NMOSFETs were investigated. It is shown that the ED location plays a crucial role in the post-ED switching function of the device, When ED occurs at the channel, the turn-on behavior of the drain current would not be significantly affected, which is in strong contrast to the case of ED at the drain. Nevertheless, significant increase in gate current is observed in the off-state when the gate voltage is more negative than -1 V, Its origin is identified to be due to the action of two parasitic bipolar transistors formed after SBD occurrence at the channel.
Process and doping species dependence of negative-bias-temperature instability for p-channel MOSFETs
(2002)
Lee, DY
;
Lin, HC
;
Chiang, WJ
;
Lu, WT
;
Huang, GW
The effects of poly-Si gate doping type and species on the negative-bias-temperature instability (NBTI) of p-channel MOS transistors were investigated. We found that, by properly suppressing boron penetration through careful thermal budget, NBTI can be reduced by proper fluorine incorporation. In addition, we found that NBTI is larger for devices with PMA annealing, thus clearly identified the role of hydrogen passivation in NBTI.