Low-Temperature PECVD SiO2 On Si And SiC

1997 ◽  
Vol 483 ◽  
Author(s):  
L. Teng ◽  
W. A. Anderson

AbstractThe deposition of SiO2 films by plasma-enhanced-chemical-vapor-deposition (PECVD) using tetraethylorthosilicate (TEOS) was studied. MOS capacitors were fabricated on both Si and SiC for this study. Several different sets of experiments were conducted for PECVD deposition according to different growth parameters and the results compared. For Si samples with SiO2 deposited at a substrate temperature 300°C, the C∼V curve gave a flat-band voltage of 1V and a transition slope of 112 pF/V. The dielectric constant of the deposited SiO2 film was 4.2 and the Si/SiO2 interface trap density was calculated to be 1.8×1010 cm−2. The I-V curve showed a leakage current density of l.2×10−9 A/cm2 and dielectric breakdown field strength of 9.2 MV/cm. For SiC samples, the PECVD deposition gave a uniform SiO2 film with a controllable deposition rate of 0.3nm/sec. The refractive index and dielectric constant of the as-deposited SiO2 film were 1.46 and 3.84 respectively. The I∼V curve showed a leakage current density of 2×10−9 A/cm2 and a breakdown field of 4.7 MV/cm.

1995 ◽  
Vol 415 ◽  
Author(s):  
Joon Sung Lee ◽  
Han Wook Song ◽  
Dae Sung Yoon ◽  
Byung Hyuk Jun ◽  
Byoung Gon Yu ◽  
...  

ABSTRACTSrTiO3 thin films were prepared on Si(p-type 100) and Pt/SiO2/Si substrates using ECR plasma (or without ECR plasma) assisted MOCVD. Sr(TMI-D)2 and Ti-isopropoxide were used as Sr and Ti metal organic sources, respectively. Perovskite SrTiO3 films were obtained at relatively low temperature of 500°C (using ECR oxygen plasma. Experimental results indicated that higher deposition temperature and ECR oxygen plasma increase the crystallinity, the dielectric constant and the leakage current density. The dielectric constant and the dielectric loss were 222 and 0.04, respectively, for 1234 Å thin SrTiO3 film (Sr/(Sr+Ti)=0.5). The leakage current density was 3.78 × 10−7 A/cm2 at 1.0V, and the dielectric breakdown field was 0.57MV/cm. SEM analyses showed that SrTiO3 films have a uniform and fine grain structure. In terms of step coverage, a lateral step coverage of 50% at 0.8 μm step (the aspect ratio was 1) was obtained with the thickness uniformity of ± 0.5% and the composition uniformity of ±1.2% at 4′′ wafer.


1996 ◽  
Vol 433 ◽  
Author(s):  
Kwangsoo No ◽  
Joon Sung Lee ◽  
Han Wook Song ◽  
Won Jong Lee ◽  
Byoung Gon Yu ◽  
...  

AbstractBa(TMHD)2, Sr(TMHD)2 and Ti-isopropoxide were used to fabricate the (SrxTi1 x)O3 and (Ba1 x Srx)TiO3 thin films. The decomposition and degradation characteristics of Ba(TMHD)2 and Sr(TMHD)2 with storage time were analyzed using a differential scanning calorimeter (DSC). The thin films were fabricated on Si(p-type 100) and Pt/SiO2/Si substrates with Ar carrier gas using ECR plasma (or without ECR plasma) assisted MOCVD. Experimental results showed that the ECR oxygen plasma increased the deposition rate, the ratio of Sr/Ti, the dielectric constant and the leakage current density of the film. The dependency of the crystallinity and the electrical properties on the Sr/Ti ratio of films were investigated. However, almost of the films deposited with Ar carrier gas had slightly high dielectric loss and high leakage current density and showed non-uniform compositional depth profiles. NH3 gas was also used to decrease the degradation of the MO-sources. Mass spectra in-situ monitoring of source vapors in ECR-PAMOCVD system were obtained. By introducing NH3 as a carrier gas, a significant improvement was achieved in the volatility and the thermal stability of the precursors, and the vaporization temperatures of the precursors were reduced compared to Ar carrier gas. The uniform compositional depth profile, less hydrogen and carbon content and the good electrical properties of (SrxTi1−x)O3 thin films were obtained with NH3 carrier gas. The (Ba1−xSrx)TiO3 thin film were fabricated to have very fine and uniform microstructure, the dielectric constant of 456, the dielectric loss of 0.0128, the leakage current density of 5.01 × 10−8A/cm2 at 1V and the breakdown field of 3.65MV/cm.


2007 ◽  
Vol 2 (2) ◽  
pp. 89-93
Author(s):  
Katia F. Albertin ◽  
M. A. Valle ◽  
I. Pereyra

MOS capacitors with TiO2 and TiO2/SiO2 dielectric layer were fabricated and characterized. TiO2 films where physical characterized by Rutherford Backscattering, Fourier TransformInfrared Spectroscopy and Elipsometry measurements. Capacitance-voltage (1MHz) and current voltage measurements were utilized to obtain, the effective dielectric constant, effective oxide thickness (EOT), leakage current density and interface quality. The results show that the obtained TiO2 films present a dielectric constant of approximately 40, a good interface quality with silicon and a leakage current density, of 70 mA/cm2 for VG = 1V, acceptable for high performance logic circuits and low power circuits fabrication, indicating that this material is a viable substitute for current dielectric layers in order to prevent tunneling currents.


1997 ◽  
Vol 12 (4) ◽  
pp. 1160-1164 ◽  
Author(s):  
Nam-Kyeong Kim ◽  
Soon-Gil Yoon ◽  
Won-Jae Lee ◽  
Ho-Gi Kim

The microstructure and electrical properties were investigated for SrTiO3(STO) thin films deposited on Pt/Ti/SiO2/Si substrates by PEMOCVD. The SrF2 phase existing in the STO films deposited at 450 °C influences the dielectric constant, dissipation factor, and leakage current density of STO films. The dielectric constant and dissipation factor of STO films deposited at 500 °C were 210 and 0.018 at 100 kHz, respectively. STO films were found to have paraelectric properties from the capacitance-voltage characteristics. Leakage current density of STO films at 500 °C was about 1.0 × 10-8 A/cm2 at an electric field of 70 kV/cm. The leakage current behaviors of STO films deposited at 500 and 550 °C were controlled by Schottky emission with applied electric field.


2001 ◽  
Vol 688 ◽  
Author(s):  
Hiroshi Funakubo ◽  
Kuniharu Nagashima ◽  
Masanori Aratani ◽  
Kouji Tokita ◽  
Takahiro Oikawa ◽  
...  

AbstractPb(Zr,Ti)O3 (PZT) is one of the most promising materials for ferroelectric random access memory (FeRAM) application. Among the various preparation methods, metalorganic chemical vapor deposition (MOCVD) has been recognized as a most important one to realize high density FeRAM because of its potential of high-step-coverage and large-area-uniformity of the film quality.In the present study, pulsed-MOCVD was developed in which a mixture of the source gases was pulsed introduced into reaction chamber with interval. By using this deposition technique, simultaneous improvements of the crystallinity, surface smoothness, and electrical property of the film have been reached by comparing to the conventional continuous gas-supplied MOCVD. Moreover, this film had larger remanent polarization (Pr) and lower leakage current density. This is owing to reevaporation of excess Pb element from the film and increase of migration on the surface of substrate during the interval time.This process is also very effective to decrease the deposition temperature of the film having high quality. In fact, the Pr and the leakage current density of polycrystalline Pb(Zr0.35Ti0.65)O3 film deposited at 415 °C were 41.4 μC/cm2 and on the order of 10−7 A/cm2 at 200 kV/cm. This Pr value was almost the same as that of the epitaxially grown film deposited at 415 °C with the same composition corrected for the orientation difference. This suggests that the polycrystalline PZT film prepared by pulsed-MOCVD had the epitaxial-grade ferroelectric properties even through the deposition temperature was as low as 415 °C. Moreover, large “process window” comparable to the process window at 580 °C, above 150 °C higher temperature and was widely used condition, was achieved even at 395°C by the optimization of the deposition condition.


2002 ◽  
Vol 748 ◽  
Author(s):  
Hiroshi Funakubo ◽  
Tomohiro Sakai ◽  
Takayuki Watanabe ◽  
Minoru Osada ◽  
Masato Kakihana ◽  
...  

ABSTRACTThin films of BIT, La-substituted BIT (BLT) and La- and V-cosubstituted BIT(BLTV) were epitaxially grown on SrRuO3//SrTiO3 substrates at 850°C by metalorganic chemical vapor deposition (MOCVD), and their electrical properties were systematically compared. All films on (100), (110) and (111)-oriented substrates were epitaxially grown with (001)-, (104)-/(014)-and (118) –preferred orientations, respectively. The leakage current density of the BLTV film was almost the same with that of the BLT film, but was smaller than that of BIT film, suggesting that the La substitution contributed to the decrease of the leakage current density especially in pseudoperovskite layer. Spontaneous polarization of the BLTV film was estimated to be almost the same with the BLT film but was smaller that that of the BIT film. This is explained by the decrease of Tc with the La substitution, while V did not contribute to the change of the Curie temperature (Tc ). On the other hand, the coercive field (Ec) value of the BLTV was smaller than that of the BIT and the BLT films. As a result, La substitution contributed to the decrease of the leakage current density together with the decrease of the spontaneous polarization due to the decrease of the Tc. On the other hand, V substitution contributes to the decrease of the defects that suppress the domain motion and increases the Ec value. Therefore, each substitution of La and V plays different roles and this contribution is remarkable for the films deposited at lower temperature.


1994 ◽  
Vol 361 ◽  
Author(s):  
Hideaki Yamauchi ◽  
Takafumi Kimura ◽  
Masao Yamada

ABSTRACTSrTiO3 thin films have been prepared by MOCVD. A novel Sr source of Sr(DPM)2-tetraen2 was used to stabilize source delivery and to reduce the vaporization temperature of Sr source. Films were deposited on Pt/Ta/Si substrates at deposition temperatures from 450 °C to 600 °C. The relative dielectric constant was about 220 at the deposition temperatures from 550 °C to 600 °C for as-deposited 90-nm-thick films. The leakage current density was in the range of 10−7 A/cm2, typically.


1994 ◽  
Vol 361 ◽  
Author(s):  
L.H. Chang ◽  
W.A. Anderson

ABSTRACTFerroelectric BaTiO3 thin films have been directly deposited on n-GaAs with carrier concentration of 5.3–8.2×1017/cm2. The BaTiO3 thin films with a thickness in the range of 80–120 nm were prepared by RF magnetron sputtering with a substrate temperature of 300°C. The as-deposited BaTiO3 films appeared to be amorphous with relative dielectric constants of around 15 and gave flat capacitance-voltage (C-V) curves, indicating poor interface properties and very high oxide charge density. After rapid thermal annealing (RTA) at 800°C for 60 sec, the relative dielectric constant of the BaTiO3 film increased to 82 and a sharp C-V curve was observed with oxide charge density of about 7×1012/cm2. However, the leakage current density increased from 4×10'11 A/cm2 for as-deposited BaTiO3 to 2×105 A/cm2 for RTA(800°C)-BaTiO3 at a field of 4×105 V/cm. By taking advantage of the best properties from both as-deposited amorphous BaTiO3 films (low leakage current density) and RTA(800°C)-BaTiO3 (high dielectric constant) the double layer structure was designed to enhance the electrical properties of the BaTiO3 films on GaAs. The most promising results in regards to the dielectric property and leakage current density are 76.5 and 9.7×109 A/cm2, respectively, for the double layer RTA(500°C)-BaTiO3 on RTA(800°C)-BaTiO3 structures.


2001 ◽  
Vol 16 (9) ◽  
pp. 2680-2686 ◽  
Author(s):  
J. S. Fang ◽  
C. T. Chang ◽  
T. S. Chin

Barium-strontium titanate (BST) thin films were prepared by a two-step deposition using radio-frequency magnetron sputtering on Pt/Ti/SiO2-buffered Si(100) substrate. The initial BST layer thickness and intermediate annealing strongly affect the resultant electric properties of the two-step BST thin films. The optimal two-step BST films, with a first-layer thickness of 30 nm intermediate annealed at 610 °C under 1 torr oxygen. The dielectric breakdown and leakage current density of the two-step film are above 625 kV/cm and 9.5 nA/cm2 at 100 kV/cm, respectively, compared with 400 kV/cm and 17 nA/cm2 for the one-step films. We conclude that the two-step deposition dramatically improves dielectric breakdown and enhances leakage current density while keeping the dielectric constant uninfluenced.


1993 ◽  
Vol 335 ◽  
Author(s):  
Z. Q. Shi ◽  
C. Chern ◽  
S. Liang ◽  
Y. Lu ◽  
A. Safari

AbstractEpitaxial strontium titanate (SrTiO3) thin films have been grown by plasma enhanced metalorganic chemical vapor deposition (PE-MOCVD) technique on different bottom electrode materials, such as Pt/MgO and YBCO/LaAlO3. The as grown SrTiO3 film exhibited an epitaxial structure with <100> orientation perpendicular to the substrates as examined by X-ray diffraction (XRD). The electrical and dielectric properties of the films were investigated by capacitance-voltage (C-V) and current-voltage (I-V) measurements in a temperature range from 80K to 300K. The dielectric constant and dielectric loss were found to be 320 and 0.08 at 100 kHz and room temperature. The dc leakage current density and breakdown voltage were strongly dependent on the choice of the bottom electrode materials. For the films grown on YBCO/LaAlO3, the leakage current density is 8.8×10−7 A/cm2 at 200 kV/cm and the breakdown voltage is about 2.0 MV/cm. These results indicated that the SrTiO3 films are suitable for many devices applications. The frequency dependence of the dielectric constant and dielectric loss were studied in the range of 12 Hz to 1 MHz at room temperature. With the increase of the frequency, the dielectric constant showed a little decrease, while the dielectric loss exhibited a sharp increase which could be attributed to the electrode resistance loss.


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