Browsing by Author "Shye, DC"

Now showing 1 - 8 of 8

Characteristics of (Pb, Sr)TiO3 films post treated by low temperature technologies
(2004)
Wang, JL
;
Jan, CK
;
Shye, DC
;
Kuo, MW
;
Cheng, HC
The novel annealing technologies, rapid thermal annealing (RTA) and excimer laser annealing (ELA) at low substrate temperature (300degreesC), were applied on the (Pb, Sr)TiO3 (PSrT) films. The PSrT film post treated by ELA only exhibits ferroelectric property and lager dielectric constant than as-deposited PSrT film. The PSrT film post treated by RTA only shows poor P-E curve and large leakage current. Interesting, the electrical properties of the PSrT film can be greatly enhanced by both of the ELA and the succeeding RTA treatments, so ferroelectric properties and dielectric constant can be reached as high as 15 muC/cm(2) of P-s and 574 of dielectric constant. In this work, excellent electrical properties of PSrT film post treated by both of ELA and succeeding RTA at low substrate temperature were systematically studied.
Characteristics of low-temperature-prepared (Ba, Sr)TiO3 films post treated by novel excimer laser annealing
(2002)
Shye, DC
;
Chiou, BS
;
Hwang, CC
;
Chen, JS
;
Su, IW
Thin (Ba0.5Sr0.5)TiO3 (BST) films were sputtered on Pt[FiN/Ti/Si multilayer substrates at very low temperature (150degrees C). A novel process, using wavelength 248-nm KrF excimer laser annealing (ELA), has been undertaken to implement barium strontium titanate (BST) films at a low process temperature of 300degrees C. The crystallinity and dielectric constant are greatly improved after ELA treatment. In this work, the variation of texture was investigated. Besides, the escaped oxygen atoms from BST films were detected in-situ using a residual gas analyzer (RGA) during ELA process. Thus, the degradation of upper surface is strongly influenced by the laser energy fluence for an ELA-BST film.
Current-temperature characteristics of low-temperature-sputtered (Ba,Sr)TiO3 films post treated by rapid thermal annealing
(2002)
Shye, DC
;
Chen, JS
;
Kuo, MW
;
Chou, BCS
;
Jan, CK
This work reports the current-temperature characteristics of the low-temperature-sputtered (Ba0.8Sr0.2)TiO3 (BST) film post treated by rapid thermal annealing (RTA) in O-2 ambient. The top electrode was biased under negative/positive voltage to investigate the interface properties of the Pt/BST/Pt multifilm. As the results, the current density of the RTA-treated BST film was greatly reduced owing to compensation of oxygen vacancies. The RTA-treated BST thin film biased at negative voltage exhibits a negative temperature-coefficient-resistivity (NTCR) behavior, but, intriguingly, that biased at positive voltage reveals a positive temperature-coefficient-resistivity (PTCR) behavior. According to the leakage current analysis, the Schottky emission dominates the negative biased current at upper interface, but the Heywang barrier scattering confines the positive biased current.
Dependence of polarization on temperature coefficient resistance of (Ba, Sr)TiO3 thin films post-treated by RTA
(2003-04-01)
Shye, DC
;
Chiou, BS
;
Kuo, MW
;
Chen, JS
;
Chou, BCS
The temperature coefficient of resistance (TCR) characteristics of Pt/(Ba0.8Sr0.2)TiO3 (BST)/Pt thin-film resistors are studied for the BST films with rapid thermal annealing (RTA) treatments. The polarizations induced by bias voltages greatly influence the TCR characteristics. The RTA-treated BST thin film exhibits negative TCR (NTCR) behavior at a negative voltage, but, intriguingly, positive TCR (PTCR) behavior at a positive voltage. According to the leakage current analysis, Schottky emission dominates the negatively biased current at the upper interface, but Heywang barrier scattering confines the positive biased current. (C) 2003 The Electrochemical Society.
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 thermal stabilities for the ultra thin chromium layers applied on (Ba,Sr)TiO3 thin films
(2004)
Kuo, MW
;
Shye, DC
;
Chiou, BS
;
Chen, JS
;
Cheng, HC
This work reports the temperature-electric properties for the (Ba,Sr)TiO3(BST) thin film capacitor using the multi-film structure of BST/ultra-thin-chromium(Cr) layer/BST. The BST(200 nm)/Cr(1-3 nm)/BST(200 nm) multi-films reveal excellent properties in the thermal stabilities of dielectric property, low leakage current and less power dissipation.
Low temperature radio-frequency-sputtered (Ba, Sr)TiO3 films on Pt/TiN/Ti/Si substrates with various oxygen/argon mixing ratios
(2003-02-01)
Shye, DC
;
Chiou, BS
;
Lai, MJ
;
Hwang, CC
;
Jiang, CC
(Ba, Sr) TiO3 (BST) films were fabricated on Pt/TiN/Ti/Si substrates by low temperature radio frequency magnetron cosputtering at 300degreesC. Material and electrical properties of BST films sputtered at low temperatures are significantly affected by the O-2/(Ar + O-2) mixing ratio (OMR). Plasma emission spectra indicate that the deposition rate declines at a higher OMR due to oxide formation on the target surface. The dielectric constant of the BST films can reach a maximum of 364 at 5% OMR. The ten-year lifetime of the time-dependent dielectric breakdown implies that the reliability of the capacitor can be enhanced at a higher OMR due to compensation of oxygen vacancies and smaller grain sizes. Current-voltage analysis indicates that the leakage current of the Pt/BST/Pt capacitor is limited by Schottky emission (SE)/Poole-Frenkel emission (PF) at a lower/higher applied field. The applied field boundary between SE and PF shifts toward higher field as OMR increases. Moreover, an energy band model was proposed and this leakage mechanism was discussed. (C) 2003 The Electrochemical Society.
The effects of post excimer laser annealing on (Ba,Sr)TiO3 thin films at low substrate temperatures
(2003-04-01)
Shye, DC
;
Chiou, BS
;
Hwang, CC
;
Jaing, CC
;
Hsu, HW
The amorphous (Ba,Sr)TiO3 (alpha-BST) films sputtered onto the Pt/TiN/Ti/Si substrates are greatly improved using the excimer laser annealing (ELA) technique of wavelength 248 nm at low substrate temperature 300degreesC. The dielectric constant of the alpha-BST film is remarkably enhanced from 80 to over 250 after ELA treatment. The heat conduction analysis indicates that a very shallow light absorption depth of the wavelength 248 nm for the BST film behaves an excellent thermal property, which doesn't,damage the underlayer films during ELA treatment. Besides, the leakage current of ELA-BST films is strongly influenced by the laser energy fluence (LEF). The detailed mechanisms of the crystallinity and the electric properties am systematically studied in this report.