Browsing by Author "Yang, WJ"

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A new physical and quantitative width dependent hot carrier model for shallow-trench-isolated CMOS devices
(2001)
Chung, SS
;
Chen, SJ
;
Yang, WJ
;
Yang, JJ
;
電子工程學系及電子研究所
In this paper, we present new results on the width dependent hot-carrier (HC) degradation for shallow-trench-isolated (STI) CMOS devices. Experimental data shows that the drain current degradation is enhanced for a reducing gate width. New models and mechanisms are proposed to explain the width dependent degradation for both n-channel and p-channel MOSFET's, where new monitors are developed for both types of devices respectively. In fi-MOSFET's, the interface state generation at the STI-edge is enhanced for narrow width device. However, for p-MOSFET's, a two-dimensional channel shortening model is introduced. The channel shortening induced oxide damage is the dominant mechanism for the drain current degradation. Both are found to be strongly related to the mechanical stress on the border of the trench. This is a very crucial issue for the present and future CMOS ULSI using STI technologies.
An accurate hot carrier reliability monitor for deep-submicron shallow S/D junction thin gate oxide n-MOSFET's
(1999)
Chung, SS
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Chen, SJ
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Yih, CM
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Yang, WJ
;
Chao, TS
In this paper, an accurate criterion has been proposed for reliability evaluation of state-of-the-art deep-submicron S/D extension n-MOSFET's. A new monitor for HC reliability evaluation has been developed using total values of N-it in the effective channel length region, instead of commonly used substrate current(I-B), impact ionization rate (I-D/I-B), or peak/average N-it values. An accurate degradation model has thus been developed based on the N-it distribution and mobility scattering effect. Moreover, this approach has been successfully used to demonstrate the feasibility for gate-engineering studies.
Luminescence and energy transfer of Eu- and Mn-coactivated CaAl2Si2O8 as a potential phosphor for white-light UVLED
(2005-07-26)
Yang, WJ
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Luo, LY
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Chen, TM
;
Wang, NS
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應用化學系
A series of Eu2+- and Mn2+-coactivated CaAl2Si2O8 phosphors have been synthesized at 1400 degrees C under a reduced atmosphere and their luminescence properties have been investigated as a function of activator and coactivator concentrations. We have discovered that energy transfers from Eu2+ to Mn2+ by directly observing significant overlap of the excitation spectrum of Mn2+ and the emission spectrum of Eu2+ as well as the systematic relative decline and growth of emission bands of Eu2+ and Mn2+, respectively. The critical distance and average separation of Eu2+ and Mn2+ have also been calculated. By utilizing the principle of energy transfer, we have also demonstrated that with appropriate tuning of activator content CaAl2Si2O8:Eu2+ Mn2+ phosphors exhibit great potential to act as a phosphor for white-light ultraviolet light-emitting diodes (UVLEDs).
New degradation mechanisms of width-dependent hot carrier effect in quarter-micron shallow-trench-isolated p-channel metal-oxide-semiconductor field-effect-transistors
(2001-01-01)
Chung, SS
;
Chen, SJ
;
Yang, WJ
;
Yih, CM
;
Yang, JJ
In this study, width-dependent hot-carrier degradation in the p-channel metal-oxide-semiconductor held-effect transistors (p-MOSFETs) with shallow-trench-isolation (STI) is presented. Results show an enhanced drain current degradation with reducing the gate width. A new model and mechanism are proposed to explain the width-dependent hot-carrier (HC) degradation for p-MOSFETs. Based on a two-dimensional channel shortening concept, a new model is developed. The mechanical stress enhanced oxide damage at the STI edge, which will induce channel shortening, is the dominant mechanism for the drain current degradation of the devices after hot-carrier stress. This is a crucial issue for present and future complementary metaloxide semiconductor (CMOS) ultra-large-scale integration (ULSI), and in particular for high-density dynamic random-access memory (DRAM), fabricated using STI technologies.
White-light generation and energy transfer in SrZn2(PO4)(2): Eu,Mn phosphor for ultraviolet light-emitting diodes
(2006-03-06)
Yang, WJ
;
Chen, TM
;
應用化學系
;
Department of Applied Chemistry
The SrZn2(PO4)(2):Eu2+,Mn2+ phosphor shows two emission bands under ultraviolet radiation; the one observed at 416 nm is attributed to Eu2+ occupying the Sr2+ sites and the other asymmetric band deconvoluted into two peaks was found to center at 538 and 613 nm, which originate from Mn2+ occupying two different Zn2+ sites. The energy transfer from Eu2+ to Mn2+ has been demonstrated to be a resonant type via a dipole-quadrupole mechanism. By utilizing the principle of energy transfer and appropriate tuning of activator contents, we have demonstrated that SrZn2(PO4)(2):Eu2+,Mn2+ is potentially useful as an ultraviolet-convertible phosphor for white-light emitting diodes. (c) 2006 American Institute of Physics.