Browsing by Author "Chang, YF"

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Device characteristics and aggravated negative bias temperature instability in p-channel metal-oxide-semiconductor field-effect transistors with uniaxial compressive strain
(2006-04-01)
Lu, CY
;
Lin, HC
;
Chang, YF
;
Huang, TY
;
電子工程學系及電子研究所
P-channel metal-oxide-semiconductor field-effect transistors (PMOSFETs) featuring poly-SiGe gates and compressive strain channels were investigated. The compressive strain in the channel was deliberately induced in this study by a plasmaenhanced chemical vapor deposition (PECVD) silicon nitride (SiN) capping layer over the gate. Our results indicate for the first time that, while strain channel engineefing serves as an effective method to enhance drive current for scaled complementary metal-oxide-scmiconductor (CMOS) devices consistent with literature reports, it also simultaneously aggravates the negative bias temperature instability (NBTI) of scaled devices. The aggravated NBTI behavior is ascfibed to a higher amount of hydrogen incorporation during SiN deposition as well as a higher strain energy stored in the channel. Saturation phenomena in the shift of threshold voltage and generation of interface states are observed at high stress temperatures and long stress times. Moreover, transconductance degradation in devices with SiN capping is greatly aggravated under high temperature stress.
Modified double-layer PECVD passivation films for improving nonvolatile memory IC performance
(1997)
Lin, CF
;
Tseng, WT
;
Feng, MS
;
Chang, YF
;
交大名義發表
Characteristics of PECVD SiO2SiNx passivation layers are modified to improve and optimize electrical performances such as read-write (R/W) cycle and hot carrier reliability of floating-gate nonvolatile memory devices. SiH4/N2O gas mixtures are utilized as precursors for oxide CVD process. Higher SiH4/N2O flow rate ratios render the resulting oxide films more silicon-rich, as manifested by their higher refractive index (R.L) and wet etch rates. These modifications in film characteristics also correspond to longer R/W cycles and lower % hot-carrier linear drain current (I-dlin) degradation. An increase in R.I, from 1.520 to 1.675 translates to a rise in R/W cycles from 17.3K to 32K and a fall in I-dlin from 8.2 % to 4.9 %. Further improvement in device performance is fulfilled by modifying the stoichiometry of the overlying nitride passivation layer. This is achieved by increasing bias power while reducing SiH4/NH3 gas flow rate ratio during the PECVD nitride deposition process. The nitride films deposited herein contain lower hydrogen content and exhibit lower BOE etch rates and compressive stress. Water diffusion from oxide and hydrogen release from nitride are both responsible for hot carrier drain current degradation and loss in read-write cycles. The utilization of high-RI oxide in conjunction with a low hydrogen content nitride would yield the optimal device reliability.
The development of an online adaptive questionnaire for health education in Taiwan
(2000-11-01)
Chou, C
;
Chang, YF
;
Jiang, YY
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傳播研究所
;
Institute of Communication Studies
This paper explores the feasibility and usability of using computer networks, in particular the World Wide Web, as educational survey research instruments to collect students' opinions on proposed health education courseware. Also covered are the review of computer-assisted survey techniques, and the comparisons among different survey methods. The development and the evaluation of a Web-based adaptive questionnaire for health education are presented. Research issues are also discussed. (C) 2000 Elsevier Science Ltd. All rights reserved.
ULSI multi-layer thin film passivation processes for improving cache memory performance
(1998)
Lin, CF
;
Tseng, WT
;
Feng, MS
;
Chang, YF
;
Hsu, JJ
A multi-layer thin film structure based on PECVD SiO2/SiNx layers are deposited and characterized, in order to improve and optimize the electrical performance and hot carrier reliability of poly load resistors in 4-transistor (4-T) cache Static Random Access Memory (SRAM) devices. SiH4/N2O gas mixtures are utilized as precursors for oxide CVD process. Higher SiH4/N2O flow rate ratios render the resulting oxide films more silicon-rich, as manifested by their higher refractive index (R.I.) and BOE etch rates. These modifications in film characteristics also correspond to enhanced resistance of poly load resistor and lower % hot-carrier linear drain current (I-dlin) degradation. An increase in R.I. from 1.46 to 1.60 translates to a rise in resistance of poly load resistor from 98 Ga to 225 G Omega and a fall in I-dlin from 5.8 % to 4.5 %. Further improvement in device performance can be fulfilled by modifying the stoichiometry of the overlying nitride passivation layer. This is achieved by increasing bias power while reducing SiH4/NH3 gas flow rate ratio during the PECVD nitride deposition process. The nitride films thus deposited contain lower SI-H bond density, and exhibit lower BOE etch rates and compressive stress. Passivation structures based on the combination of a high RI SRO with a tow Si-H content nitride layers yield the most promising device performance and reliability. Water and hydrogen diffusion to the poly gate and load resistor are both held responsible for device degradation.