Browsing by Author "Liu, DG"

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Barrier capability of TaNx films deposited by different nitrogen flow rate against Cu diffusion in Cu/TaNx/n(+)-p junction diodes
(2001-01-01)
Yang, WL
;
Wu, WF
;
Liu, DG
;
Wu, CC
;
Ou, KL
This paper investigates the barrier capability of tantalum nitride (TaNx) layers against Cu diffusion. The TaNx layers were reactively sputtered in contact holes to a thickness of 50 nm by using a different nitrogen flow rate. Results indicate that the TaNx layers fail to be a diffusion barrier due to a relative high resistivity for nitrogen flow ratios exceeding 10%. in addition, we found that the phase of alpha -Ta(-N) functions as an effective barrier against Cu diffusion and that Cu/TaN(3-5%)/n(+)-p junction diodes are able to sustain a 30 min furnace anneal up to 500 degreesC without causing degradation of the electrical characteristics. The high-temperature failure of barrier capability for the TaNx layers is due to interdiffusion of Cu and Si across the TaNx film structure to form Cu3Si. The surface roughness and the film structure of TaNx layers determine the ability of Cu and Si interdiffusion. (C) 2001 Elsevier Science Ltd. All rights reserved.
Improvement of polysilicon oxide integrity using NF3-annealing
(2000-06-15)
Yang, WL
;
Shieh, MS
;
Chen, YM
;
Chao, TS
;
Liu, DG
We report a method to improve the polysilicon oxide integrity by using NF3-annealing. Incorporating with stronger Si-N and Si-F bonds at the polysilicon/polyoxide interface, significant improvements are found in terms of roughness, breakdown strength, charge-to-breakdown, and stress-induced-leakage-current.
Retardation in the chemical-mechanical polish of the boron-doped polysilicon and silicon
(2000-05-01)
Yang, WL
;
Cheng, CY
;
Tsai, MS
;
Liu, DG
;
Shieh, MS
;This letter reports on the chemical-mechanical polishing (CMP) of boron doped polysilicon and silicon. Successive polishing was carried out to investigate how the removal rate correlates to the boron concentration as a function of depth in the polysilicon and crystalline silicon. It is found that the removal of baron-doped samples is significantly retarded and strongly correlated with the doping concentration. To the author's knowledge, this work is the first report discussing the retardation effect of boron in the Si-CMP process, This effect is attributed to the activated dopant atoms which are conjectured to inhibit the hydrolysis reaction of Si-Si bonding in the alkaline aqueous solution. In our study, the retardation effect is evident for the boron concentration higher than 5 x 10(18) cm(-3). As a consequence, it may become an issue in CMP process for those layers of selected or complemented doping.
Simulation and analysis of the capacitance-voltage characteristics of the delta-doped semiconductors
(1997-10-15)
Liu, DG
;
Lee, CP
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In this paper, a self-consistent model to simulate the general characteristics of one-dimensional semiconductor structures is demonstrated. During calculation, possible quantum effects and the distributions of both electrons and holes are all considered. In this model, a continuity equation is solved to calculate the distribution of free electrons and holes, The possible quantum wells are sought using the Schrodinger equation. The overall charge density and potential are obtained self-consistently by an iteration scheme. The C-V characteristics of the delta-doped structures are simulated and then compared with those of practical samples. By comparing with these delta-doped samples, the effective numbers of dopant atoms can be precisely determined. For these highly doped samples, it is found that the activation rates are only about half. This finding can be verified by Hall measurements which confirms the accuracy in this study. (C) 1997 Elsevier Science S.A.
Simulation and analysis of the capacitance-voltage characteristics of the delta-doped semiconductors
(1997-10-15)
Liu, DG
;
Lee, CP
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In this paper, a self-consistent model to simulate the general characteristics of one-dimensional semiconductor structures is demonstrated. During calculation, possible quantum effects and the distributions of both electrons and holes are all considered. In this model, a continuity equation is solved to calculate the distribution of free electrons and holes, The possible quantum wells are sought using the Schrodinger equation. The overall charge density and potential are obtained self-consistently by an iteration scheme. The C-V characteristics of the delta-doped structures are simulated and then compared with those of practical samples. By comparing with these delta-doped samples, the effective numbers of dopant atoms can be precisely determined. For these highly doped samples, it is found that the activation rates are only about half. This finding can be verified by Hall measurements which confirms the accuracy in this study. (C) 1997 Elsevier Science S.A.
Suppression of boron penetration by using inductive-coupling-nitrogen-plasma in stacked amorphous/polysilicon gate structure
(1997-06-19)
Yang, WL
;
Lin, CJ
;
Chao, TS
;
Liu, DG
;
Lei, TF
A method is introduced for suppressing the penetration of boron for BF2+-implanted pMOS devices with a stacked amorphous/ poly-Si (SAP) gate structure. It is shown that after inductive-coupling-nitrogen-plasma (ICNP) treatment, boron diffusion through the thin gale oxide is largely suppressed. As shown from the charge-to-breakdown measurements, the ICNP process will improve the quality of pMOS devices, with Q(bd) three times higher than for the control samples.