Increasing Rapid Thermal Annealing Temperature Research Articles

High Device Yield of Resistive Switching Characteristics in Oxygen-Annealed $\hbox{SrZrO}_{3}$ Memory Devices

This paper reports the effects of rapid thermal annealing (RTA) on resistive switching (RS) characteristics and mechanisms of SrZrO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> (SZO)-based memory devices. SZO thin films were deposited on LaNiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> (LNO) (100)/Pt/Ti/SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /Si using radio-frequency magnetron sputtering and were followed by an RTA process in N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> , Ar, and O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ambients, respectively, at various temperatures for improving RS performance. Experimental results indicate that an SZO device annealed in O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> at 600°C (O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -600) exhibits stable RS properties and has a high device yield ( 90%), a reliable retention characteristic (up to 1 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sup> s at 100°C), and steady nondestructive readout properties (over 1.4 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> s at 100°C). However, by increasing RTA temperature to more than 700°C, random formation of LNO (110) precipitates on the bottom surface of SZO grains might shorten the effective thickness of the SZO thin films. Furthermore, a strong electric field possibly occurs at the region between Al top electrodes and low-resistivity LNO precipitates. It is speculated that an RS phenomenon, which occurs within SZO grains instead of on grain boundaries, easily leads to RS failure, further resulting in severe degradation of device yield in the O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -700 and O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -800 devices. When compared with other devices, O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -600 SZO memory devices exhibit highly reliable RS characteristics.

Shift in room-temperature photoluminescence of low-fluence Si+-implanted SiO2 films subjected to rapid thermal annealing

We experimentally demonstrate the effect of the rapid thermal annealing (RTA) in nitrogen flow on photoluminescence (PL) of SiO2 films implanted by different doses of Si+ ions. Room-temperature PL from 400-nm-thick SiO2 films implanted to a dose of 3×1016 cm−2 shifted from 2.1 to 1.7 eV upon increasing RTA temperature (950–1150 °C) and duration (5–20 s). The reported approach of implanting silicon into SiO2 films followed by RTA may be effective for tuning Si-based photonic devices.

Nitrogen-dependent effects on GaInNAs photoluminescence upon annealing

In order to assess the effects of nitrogen on GaInNAs during the annealing process, we analyzed several quantum wells (QWs) with different nitrogen contents after annealing at different rapid thermal annealing (RTA) conditions. When only the RTA temperature was varied, we found two blueshift regimes. Up to 700 °C (strong blueshift regime), the blueshift experiences a rapid increase with increasing RTA temperature, while above this temperature (weak blueshift regime) it saturates. The activation energies of the blueshift mechanism in the strong blueshift regime decrease with increasing nitrogen content. In the weak blueshift regime, the blueshift saturates more slowly with respect to RTA temperature and to higher values the higher the nitrogen content. When only the RTA time was changed, the blueshift again saturated to higher values the more the nitrogen content. The photoluminescence (PL) efficiency improvement is, on the other hand, unaffected by the nitrogen concentration and depends only on the RTA conditions used. Moreover, short-time annealing at high temperatures results in a smaller PL broadening and is therefore preferable for the growth of active GaInNAs. In outdiffusion from the QW is evident only for long-time annealing. Therefore, the blueshift effects seen for the short-time annealing are related to a different mechanism.

Impurity free vacancy disordering of InAs/GaAs quantum dot and InAs/InGaAs dot-in-a-well structures

Two types of InAs quantum dot (QD) structure, grown by molecular-beam epitaxy on GaAs (100) substrates, one with dot-in-a-In 0.12Ga 0.88As quantum well (QW) and another one with dots embedded in a GaAs matrix, were intermixed by impurity free vacancy disordering method using SiO 2 dielectric capping and rapid thermal annealing (RTA). The material and optical qualities of these structures were examined and compared by transmission electron microscopy (TEM) and low-temperature 5 K photoluminescence (PL) measurements. For both structures, significant blueshift of the PL spectra with increasing RTA temperature is observed. A maximum blueshift of up to 325 nm is observed from the InAs/InGaAs structure at a RTA temperature of 900 °C. Deduced from the reduction in dot height/diameter aspect ratio by TEM study and the reduction in PL peak separation for ground and excited states, it appears that QDs in dot-in-a-GaAs structure dissolved in a faster rate with increasing RTA temperature, attributed to the higher strain-induced interdiffusion in the InAs/GaAs structure. As opposed to InAs/GaAs QDs, InAs/InGaAs dots-in-a-well retained their optical quality and structural sharpness even after transforming into a QW at high annealing temperature, thus making this structure better candidate for monolithic photonic integration.

Effect of Indium on Photoluminescence Properties of InGaPN Layers Grown by Solid Source Molecular Beam Epitaxy

The effect of indium on photoluminescence properties of InGaPN layers was investigated and compared with that of GaPN layers. Two phenomena involving photoluminescence properties were observed in the InGaPN layers: (i) an S-shape of photoluminescence (PL) peak energy as a function of temperature, caused by spatial fluctuation of bandgap energy related to In and N content; and (ii) red shifts of the PL peak energy at 18 K in the InGaPN layers after rapid thermal annealing (RTA), caused by the increase of N- and In-rich region with increasing RTA temperature. It was also found that integrated PL intensity in the InGaPN layers was higher than that in the GaPN layers, and that PL quenching became more insensitive to the change in temperature resulting from the decrease in nonradiative centers with increasing RTA temperature.

Microstructure and Electrical Properties of BLT Films by Chemical Solution Deposition

ABSTRACT The phase formation and electrical properties of (Bi,La)4Ti3O12 (BLT) thin film prepared by the chemical solution deposition method on Pt/TiO2/SiO2/Si substrates have been investigated. It was observed that the microstructure and electrical properties of BLT thin films dramatically varied with rapid thermal annealing (RTA) temperature. The crystallinity and grain size of BLT thin films were definitely increased with increasing RTA temperature of BLT films, which resulted in the enhancement of remanent polarization in BLT films. The remanent polarization (Pr) of BLT films annealed at 800°C by an RTA system was about 10 μ C/cm2. The leakage current densities of BLT films annealed above 750°C are 1∼ 3 × 10− 7A/cm2 at the applied field of 100 kV/cm. The polarization loss of BLT thin films after 1010 switch cycles is observed to slightly increase with increasing RTA temperature.

Effect of excess Pb on fatigue properties of PZT thin films prepared by rf-magnetron sputtering

The effects of post-annealing temperature of sputtered Pb(Zr,Ti)O 3 (PZT) thin films on the fatigue properties were investigated. The crystallization process and fatigue properties of PZT thin films strongly depended on the rapid thermal annealing (RTA) temperature . In the sputtering methods, excess Pb was added into the target because the post-annealing treatments promote the Pb volatilization of PZT thin films. The X-ray photoelectron spectroscopy (XPS) analysis showed that Pb content of film surface was decreased with increasing RTA temperature. We found that fatigue properties of PZT thin films were strongly affected by Pb-rich layer.

Red-light emission in MCM-41 meso-porous nanotubes

Photoluminescence has been used to study the red-light emission from siliceous MCM-41 with rapid thermal annealing (RTA). A broad emission ranging from 580 to 670 nm was observed and interpreted as non-bridging oxygen hole center (NBOHC). Based on the evolution of NBOHC after RTA, the hydroxyl group and peroxy linkage were demonstrated to be the possible precursors of NBOHC in siliceous MCM-41. We also found the photoluminescence intensity of NBOHC in MCM-41 degrade with time during photoexcitation. The degradation rate of NBOHC increases with increasing RTA temperature and excitation power. The degradation mechanism of photoluminescence may be associated with the recombination of the optically induced hydrogen species and NBOHC.

Raman Scattering and Photoluminescence of Mg-Implanted GaN Films

As-grown highly resistive (>107 Ω cm) GaN samples were exposed to implantation of 24Mg+ ions with the energy of 120 keV and dose of 2 × 1014 cm—2. Isochronal rapid thermal annealing (RTA) was carried out for the Mg-implanted samples at 850, 950 and 1050 °C, respectively. Under z(x, x)z′ backscattering configuration, A1(LO) and E2(high) Raman modes of 735 cm—1 and 569 cm—1, respectively, were observed for the as-grown and Mg-implanted samples, but a Raman mode of 662 cm—1 appeared only in the implanted samples. We tentatively assigned the mode to a Mg acceptor-related vibration mode. Room temperature photoluminescence revealed that the as-grown films displayed a strong yellow luminescence of 560 nm (2.21 eV), while Mg-implanted samples only exhibited a broad blue-violet luminescence peaking at 400 nm (≈3.11 eV) which decreased with increasing RTA temperature. Our observation supported the Ga vacancy model responsible for yellow luminescence.

Effects of Rapid Thermal Annealing on the Electrical Properties of Cobalt Contact to p-GaN

The effects of rapid thermal annealing (RTA) on Co/p-GaN contacts in an O2/N2 atmosphere without intermediate metal were investigated. It was observed that the contact resistance (ρc) decreased with increasing RTA temperature and that the resistance was reduced by a factor of about 30 after RTA at 600°C in the O2/N2 atmosphere. The specific minimum contact resistance was in the 10-2 Ω·cm2 range. Comparison of the R0 and ρc values revealed that the rapid thermal annealing in the O2/N2 was more effective for reducing the contact resistance than conventional furnace annealing. The reason for the reduction of resistance was expected to be the increase of hole concentration due to the highly reactivated removal of hydrogen atoms in the p-GaN by RTA in the O2/N2 atmosphere.

Blue to red electroluminescence from Au/native silicon oxide/p-Si structure subjected to rapid thermal annealing

Blue, green, yellow and red electroluminescence (EL) from the semitransparent Au/native silicon oxide (NSO)/p-Si structure was observed. The p-Si wafers with NSO films were subjected to rapid thermal annealing (RTA) at a series of temperatures between 600 and 1000°C and then the semitransparent Au/NSO/p-Si structure was made. Under forward biases over 3 V, strong EL could be observed. The effect of RTA temperature on EL spectra of the semitransparent Au/NSO/p-Si structure was studied. It was found that with increasing RTA temperature from 600 to 900°C, wavelength of the main EL peak varied between 460 and 680 nm and intensity of the main EL peak increased monotonously.

Fourier transform infrared study of rapid thermal annealing of a-Si:N:H(D) films prepared by remote plasma-enhanced chemical vapor deposition

Fourier transform infrared spectroscopy has been used to study the behavior of bonded hydrogen and bonded deuterium in hydrogenated amorphous silicon nitride films [a-Si:N:H(D)] that were deposited by remote plasma-enhanced chemical vapor deposition (RPECVD) and had been subjected to rapid thermal annealing (RTA) from 400 to 1200 °C after film deposition. The amount of bonded hydrogen in the film and its distribution between Si–H and SiN–H bonding groups is correlated to the ratio (R) of the source gases: NH3 to SiH4. Chemical reaction pathways are proposed to account for bond dissociation and release of hydrogen from the films in the form of molecular H2 and NH3. As the bonded hydrogen population decreases with increasing RTA temperature, the Si–N bond population increases. This postdeposition bonding of nitrogen to silicon upon thermal release of hydrogen species is consistent with improvements in the electrical properties of RPECVD silicon nitride films after an RTA treatment at 900 °C.

Effect of rapid thermal annealing on gate induced drain leakage in a n-channel metal-oxide-semiconductor field effect transistor

Significant gate induced drain leakage caused by post-oxide rapid thermal annealing (RTA) was studied in this letter in comparison with the non-RTA process for n-channel metal-oxide- semiconductor field effect transistor. It is found that the sub-breakdown leakage increases with increasing RTA temperature. We proposed that interface states and recombination centers generated after RTA are the dominant factors in the enhancement of the leakage current. In addition, it is found that RTA has no effect on the avalanche breakdown voltage.

Analysis of the structure and defects in heteroepitaxial Si/CoSi 2/Si layers produced by ion beam synthesis and rapid thermal annealing

The effects of rapid thermal annealing (RTA) on the microstructure and electrical properties of ion-beam-synthesized silicide layers fabricated using cobalt doses of 7×10 17, 5×10 17 and 1.5×10 17 cm −2 at an energy of 200 KeV have been studied. For all three doses, increasing RTA temperature leads to the chemical segregation of the implanted cobalt—via the thermodynamically controlled dissolution of the small CoSi 2 precipitates in the wings of the distribution. Likewise, increasing the anneal temperature affects the removal of defects lying on Si{311} lattice planes, which are created by an excess of silicon self-interstitials. For the two highest doses, the phase transformation CoSi→ CoSi 2 is also facilitated by increasing anneal temperature. In all cases, it is found that the resistivity and crystallinity of the layers are critically dependent on the Co:Si ratio, with high quality low resistivity layers only being attained when this is close to 1:2, i.e. CoSi 2. After RTA at 1000 °C for 5 s, stoichiometric CoSi 2 layers were achieved for all doses, with layer thicknesses ranging from 600 to 18000 Å. The value of resistivity and crystallinity obtained for the medium dose specimen (5 × 10 17 cm −) were close to those achieved by conventional furnace annealing, with those for the higher and lower doses being slightly higher.