Browsing by Author "Juang, MH"

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A novel process to form cobalt silicided p(+) poly-Si gates by BF2+ implantation into bilayered CoSi/a-Si films and subsequent anneal
(1998-07-01)
Lai, WK
;
Liu, HW
;
Juang, MH
;
Chen, NC
;
Cheng, HC
A novel process that implants BF2+ ions into thin bilayered CoSi/a-Si films has been shown to form cobalt silicided pf poly-Si gates with excellent gate oxide integrity and very small flatband shift. The effects of not only using the CoSi layer as an implantation barrier but also keeping the a-Si underlayer during the initial silicide formation both significantly suppress the boron penetration through thin gate oxide.
Effect of rapid thermal annealed TiN barrier layer on BST capacitors prepared by RF magnetron cosputter system at low substrate temperatures
(2000-12-01)
Hwang, CC
;
Jaing, CC
;
Lai, MJ
;
Chen, JS
;
Huang, S
This work reports on rapid-thermal-annealed TiN as a barrier for Pt/BST/Pt/TiN/Ti/Si capacitors. Experimental results indicate that the diffusion of Ti and Si from the Ti adhesion layer and Si plug, respectively, degrade the capacitor for the gigabit dynamic random access memories (DRAMs) using barium strontium titanate (BST) as a dielectric material. Although the diffusion barrier TiN between the bottom electrode Pt and Ti adhesion layer has been conventionally used to release the issue, the interdiffusion of Ti and Si occurs due to the thermal budget of the BST deposition. A rapid thermal annealing process is applied to the as-deposited TiN barrier against the interdiffusion. Excellent electrical characteristics, including high dielectric constant (epsilon (r) = 320), low leakage current (1.5 x 10(-8) A/cm(2)) under 0.1 MV/cm, and a lifetime greater than 10 years under 1.5 MV/cm are obtained. Our results further demonstrate that the proposed technique is highly promising for future high-density DRAMs. (C) 2000 The Electrochemical Society. S1099-0062(00)07-005-X. All rights reserved.
Effect of rapid-thermal-annealed TiN barrier layer on the Pt/BST/Pt capacitors prepared by RF magnetron co-sputter technique at low substrate temperature
(2001-01-01)
Hwang, CC
;
Juang, MH
;
Lai, MJ
;
Jaing, CC
;
Chen, JS
This investigation reports the effect of rapid-thermal-annealing (RTA) on metallic barrier TiN against the interdiffusions of Ti and Si into barium strontium titanate (BST) in Pt/BST/Pt/TiN/Ti/Si capacitors. In the integration of BST capacitors, the thermal budget of the BST deposition would cause the inter-diffusions of Ti and Si from Ti adhesion layer and Si plug respectively. This event would degrade the BST capacitors. To address this issue. rapid-thermal-annealed TiN barriers were deposited between the bottom electrode Pt and adhesion layer Ti. Optimal RTA condition for TiN were found ill this: experiment. Excellent electrical characteristics of Pt/BST/Pt/TiN/Ti/Si capacitors. including high dielectric constant (epsilon (r) = 320). low leakage current (1.5 x 10(-8) A/cm(2)) under 0.1 MV/cm, and greater than 10 year lifetime under 1.6 MV/cm were obtained with Ar + O-2 mixed ambient at a low substrate temperature (300 degreesC). (C) 2001 Elsevier Science Ltd. All rights reserved.
Effects of CoSi2 on p(+) polysilicon gates fabricated by BF2+ implantation into CoSi amorphous Si bilayers
(1998-10-01)
Cheng, HC
;
Lai, WK
;
Liu, HW
;
Juang, MH
;
電子工程學系及電子研究所
The integrity of thin gate oxide structures fabricated by implanting BF2+ ions into bilayered CoSi/amorphous silicon films and subsequent annealing has been studied as a function of cobalt silicide thickness and implantation energy. Significant degradation of gate oxide integrity and flatband voltage shifts were found with increasing cobalt silicide thickness and annealing temperature. It is shown that although thinner cobalt silicide can result in excellent gate dielectric integrity it also leads to worse thermal stability at a high annealing temperature. Moreover, shallower implantation depth and lower annealing temperature can reduce the boron penetration, but depletion effects in polycrystalline silicon gates are caused accordingly. Hence, appropriate process conditions, involving trade-offs among CoSi2 thickness, implantation energy and annealing temperature, must be used to optimize the device performance while retaining the thin dielectric reliability.
Effects of post-oxygen plasma treatment on Pt/(Ba,Sr)TiO3/Pt capacitors at low substrate temperatures
(2003-02-01)
Shye, DC
;
Hwang, CC
;
Lai, MJ
;
Jaing, CC
;
Chen, JS
We investigated how oxygen plasma post-treatment improves leakage characteristics of Pt/(Ba,Sr)TiO3 (BST)/Pt capacitors prepared by the radio-frequency (RF) cosputtering technique. Experimental results indicate that oxygen plasma treatment can effectively passivate the oxygen vacancies of (Ba,Sr)TiO3 (BST) films, thus decreasing the electric conduction paths of leakage currents. By this low-temperature (250degreesC), and short-duration (similar to5 min) process, the leakage current is reduced by as many as two orders of magnitude. The reliability characteristics of time-dependent dielectric breakdown (TDDB) are improved as well. However, the usage of oxygen plasma treatment is not unrestricted. Plasma treatment for an extended period (more than 10 min) degrades both the leakage and reliability characteristics, due to plasma damage. Excellent electrical characteristics, including low leakage current (1.5 x 10(-8) A/cm(2)) under 0.1 MV/cm, high dielectric constant (288), and a lifetime longer than 10 years under 2 MV/cm can be achieved. Therefore, the proposed technique for as-deposited BST films is a highly promising means of improving the electrical characteristics of BST thin films.
Effects of rapid thermal annealing on cobalt silicided p(+) poly-Si gates fabricated by BF2+ implantation into bilayered CoSi/a-Si films
(1999-07-01)
Lai, WK
;
Liu, HW
;
Juang, MH
;
Cheng, HC
;
電子工程學系及電子研究所
The cobalt polycide gate formed by implanting BF2+ ions into the bilayered CoSi/a-Si films and the subsequent rapid thermal anneal has been studied. The resulting gate oxide integrity is characterized with respect to various silicide thicknesses and implantation energies. Significant degradation in gate oxide integrity and Aat-band voltage shift were found with increasing silicide thickness and annealing temperature, especially for the thicker CoSi2 films, which is attributable to severe boron penetration. Although a thinner silicide can achieve excellent gate dielectric reliability, it will lead to poor high-temperature thermal stability. Moreover, shallower implantation depth and lower annealing temperature, which sustain less boron penetration, would cause the poly-Si gate depletion effects. Therefore, appropriate conditions, which comprise the CoSi2 thickness, the implantation energy, and the annealing temperature, should be employed to optimize the device performance while retaining the thin dielectric reliability.
Fabrication of trench-gate power MOSFETs by using a dual doped body region
(2004-07-01)
Juang, MH
;
Chen, WT
;
Ou-Yang, CI
;
Jang, SL
;
Lin, MJ
Fabrication of trench-gate power MOSFETs by using a dual doped body region has been proposed to further improve the device performance. For the usual scheme that employs a uniform doped body region, a device with a blocking voltage larger than 30 V and a specific on-state resistance of about 1.0 Omegacm can be obtained via the proper choice of trench depth, epitaxial thickness, and body doping concentration. On the other hand, a dual doped body region is produced by dual high-energy and low-energy implantation of boron dopant. By this scheme, a device with a blocking voltage larger than 30 V and a specific on-state resistance of about 0. 8 Omegacm can be further achieved. Hence, with reducing the cell pitch size to be below 2 mum, this device fabrication scheme should be promising and practical for achieving a specific on-resistance smaller than 0. 1 mOmegacm2 and a blocking voltage higher than 30 V. (C) 2004 Elsevier Ltd. All rights reserved.
Formation of silicided shallow p(+) n junctions by BF2+ implantation into thin amorphous-Si or Ni/amorphous-Si films on Si substrates and subsequent Ni silicidation
(1999-03-01)
Juang, MH
;
Hu, MC
;
Yang, CJ
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The process scheme that forms NiSi-silicided shallow p(+)n junctions by BF2+ implantation into thin amorphous-Si (a-Si) or Ni/a-Si films on Si substrates and subsequent Ni silicidation has been studied. As for the scheme using a-Si as an implantation barrier, an NiSi-silicided junction with a leakage of about 0.7 nA/cm(2) at - 5 V is obtained by the sample Ni silicided at 700 degrees C for 30 min. The implantation energy and the crystallinity of the deposited Si films after annealing would greatly affect the junctions formed at various temperatures, attributable to different, implantation effects and boron depth profile. However, the junctions formed by rapid thermal processing or high implant energy are considerably degraded at 800 degrees C, attributable to anomalous Ni penetration into the Si substrate with the further silicidation of NiSi into NiSi2. On the other hand, the specimens with Ni/a-Si as an implantation barrier sustain few defects, thus significantly suppressing the junction degradation at 800 degrees C. However the formed junctions are worse than those by the former scheme, mainly due to lower dopant drive-in efficiency. (C) 1999 American Vacuum Society. [S0734-211X(99)03902-5].
Low-temperature process to improve the leakage current of (Ba, Sr)TiO3 films on Pt/TiN/Ti/Si substrates
(2000-12-15)
Hwang, CC
;
Lai, MJ
;
Jaing, CC
;
Chen, JS
;
Huang, S
In this study, we employed an oxygen plasma post-treatment to improve the leakage characteristics of Pt/(Ba, Sr)TiO3(BST)/Pt capacitors prepared by the RF cosputtering technique. Applying oxygen plasma treatment to BST thin films can effectively passivate the oxygen vacancies of the BST films, thus decreasing the electric conduction paths of leakage current. The leakage current is reduced by as many as two orders of magnitude by this low-temperature (250 degreesC) and short duration (similar to5 min) process. However, the usage of oxygen plasma treatment is not unrestricted. Plasma treatment over a long time (more than 10 min) degrades the leakage characteristics, due to plasma damage. Therefore, a proper oxygen plasma treatment for as-deposited BST films is desired to improve leakage characteristics of BST thin films.
Suppression of boron penetration for p(+) stacked poly-Si gates by using inductively coupled N-2 plasma treatment
(1999-10-01)
Cheng, HC
;
Lai, WK
;
Hwang, CC
;
Juang, MH
;
Chu, SC
Nitridation of the stacked poly-Si gates by the inductively coupled N-2 plasma (ICNP) treatments has been shown to suppress the boron penetration and improve the gate oxide integrity. The ICNP treatments on the stacked poly-Si layers would create the nitrogen-rich layers not only between the stacked poly-Si layers but also in the gate oxide after post implant anneal, thus resulting in effective retardation of boron diffusion. In addition, the position of ICNP treatment closer to gate oxides leads to higher nitrogen peaks in the gate oxide region, resulting in further suppression of boron penetration and improvement of gate oxide reliability.