Browsing by Author "Yang, CK"

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A novel and direct determination of the interface traps in sub-100nm CMOS devices with direct tunneling regime (12 similar to 16A) gate oxide
(2002)
Chung, SS
;
Chen, SJ
;
Yang, CK
;
Cheng, SM
;
Lin, SH
For the first time, an improved charge pumping (CP) method has been implemented for direct determination of the interface traps in ultra-short gate length CMOS devices with ultra-thin gate oxide in the direct tunneling regime. The leakage current in a 12-16A gate oxide can be removed from the measured CP current, which enables accurate determination of the interface traps. This method has, been demonstrated successfully for various RTNO grown and RPN treated oxide CMOS devices with very thin gate oxide. Moreover, it can be used as a good monitor of ultra-thin gate oxide process and the evaluations of device reliabilities in relating to the interface trap generation.
Characteristics of top-gate polysilicon thin-film transistors fabricated on fluorine-implanted and crystallized amorphous silicon films
(1996-10-01)
Yang, CK
;
Lei, TF
;
Lee, CL
;
交大名義發表
;
電子工程學系及電子研究所
This paper presents a comprehensive study on the characteristics of n- and p-channel polycrystalline-silicon (polysilicon) thin-film transistors (TFTs) fabricated on fluorine-implanted-then-crystallized amorphous silicon films. Amorphous silicon films of two thicknesses were implanted with different energies and various dosages of fluorine, and studied using transmission electron microscopy (TEM) and secondary-ion mass spectrometry (SIMS). The electrical characteristics of TFTs fabricated on the films were correlated with the results of TEM and SIMS, It was found that field-effect mobilities of both n- and p-channel devices were improved by the fluorine implantation thanks to the enhanced grain size and the fluorine passivation effect. For the p-channel device, the fluorine implantation did not improve the subthreshold swing and even degraded it after hydrogenation. This result was thought to be caused by the fluorine-induced negative charges in oxides. However, a thin active layer and a deep implantation reduced this degradation.
Color image compression using quantization, thresholding, and edge detection techniques all based on the moment-preserving principle
(1998-02-01)
Yang, CK
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Tsai, WH
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資訊工程學系
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Department of Computer Science
A new approach to color image compression with high compression ratios and good quality of reconstructed images using quantization, thresholding, and edge detection all based on the moment-preserving principle is proposed, An input image with 24 bits per pixel is quantized into 8 bits per pixel using a new color quantization method based on the moment-preserving principle. The quantized image is then divided into n x n non-overlapping square blocks. Two representative colors for each block are computed by moment-preserving thresholding. A bit-map is then generated, consisting of 0s and 1s indicating whether the block pixels are assigned to the first color or the second according to the Euclidean distance measure. A moment-based edge detector is performed further on the bitmap of each non-uniform block. The two parameters iota and theta of a line edge with the equation of x cos theta + gamma sin theta = iota are obtained. The image is finally coded with a codebook of a 256-color palette; a 1-bit indicator for each block which specifies whether the block is uniform or not; an 8-bit color index for a uniform block, or two 8-bit color indices, a 3-bit index for theta, and a 2-bit or 3-bit index for iota for a non-uniform block. An average compression ratio of 22.49 or 33.32 can be obtained for 4 x 4 or 5 x 5 image blocks, respectively. Experimental results show the feasibility and efficiency of the proposed approach for color image compression. (C) 1998 Elsevier Science B.V, All rights reserved.
Comparison of oxide breakdown progression in ultra-thin oxide SOI and bulk pMOSFETs
(2004)
Chan, CT
;
Kuo, CH
;
Tang, CJ
;
Chen, MC
;
Wang, TH
Accelerated oxide breakdown progression in ultra-thin oxide (1.4nm) SOI pMOSFETs is observed, as compared to bulk devices. The accelerated progression is explained by the increase of hole stress current as a result of breakdown induced channel carrier heating in a floating-body configuration. Numerical simulation of hole tunneling current and hot carrier luminescence measurement are carried out to justify the proposed theory.
Low leakage reliability characterization methodology for advanced CMOS with gate oxide in the 1nm range
(2004)
Chung, SS
;
Feng, HJ
;
Hsieh, YS
;
Liu, A
;
Lin, WM
A low leakage characterization technique for the lateral profiling of interface and oxide traps in a 12Angstrom-16Angstrom range gate oxide CMOS devices has been demonstrated. The approach being taken includes an incremental frequency Charge-Pumping(IFCP) measurement and a neutralization procedure such that interface and oxide traps can be separated. The most critical steps are the elimination of leakage current during measurement and a neutralization procedure, which enables accurate detennination of interface and oxide traps. This method has been demonstrated successfully for an advanced sub-100nm CMOS devices. As an important merit for its application, evaluations of HC reliability and NBTI effect have also been demonstrated. Evaluations of gate oxide qualities with plasma nitridation in both n- and p-MOSFET reliabilities have been properly described based on the current analysis technique.
Minimum disc cover set construction in mobile ad hoc networks
(2005)
Sun, MT
;
Ma, XL
;
Yi, CW
;
Yang, CK
;
Lai, TH
The minimum disc cover set can be used to construct the dominating set on the fly for energy-efficient communications in mobile ad hoc networks. The approach used to compute the minimum disc cover set proposed in previous study has been considered too expensive. In this paper, we show that the disc cover set problem is in fact a special case of the general a-hull problem. In addition, we prove that the disc cover set problem is not any easier than the a-hull problem by linearly reducing the element uniqueness problem to the disc cover set problem. In addition to the known a-hull approach, we provide an optimal divide-and-conquer algorithm that constructs the minimum disc cover set for arbitrary cases, including the degenerate ones where the traditional alpha-hull algorithm incapable of handling.
Negative substrate bias enhanced breakdown hardness in ultra-thin oxide pMOSFETs
(2003)
Wang, TH
;
Tsai, CW
;
Chen, MC
;
Chan, CT
;
Chiang, HK
Negative substrate bias enhanced breakdown hardness in ultra-thin oxide (1.4nm) pMOS is observed. This result is believed due to the increase of hole stress current during breakdown progression via breakdown induced carrier heating. Numerical analysis of substrate bias effect on hole tunneling current is performed to support the proposed theory. This phenomenon is particularly significant to gate oxide reliability in floating substrate (PD-SOI) or forward-biased substrate devices.
New static and dynamic search algorithms for fast MP3 bit allocations
(2003)
Yang, CK
;
Chen, SG
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In this work, we propose three new static search algorithms and one dynamic search algorithm for fast bit allocation of an MP3 audio encoder. They can substantially reduce the bit allocation operations (for finding the optimal Global Gain factors) of an MP3 encoder. Specifically, the new dynamic method can reduce the loop iteration counts of the bit allocation block by up to 30% that of the current known 0(th)-order and 1(st)-order predictive search algorithms. It,is achieved by taking into account of the statistical properties of the Global Gain factors. Since generally computation time of the bit allocation loop takes up more than 70% of a complete MP3 coding process, the new algorithm is good for highspeed and low-power realization of an MP3 encoder.