Rapid Thermal Processing Chemical Vapor Deposition Research Articles

Flexible and lightweight graphene grown by rapid thermal processing chemical vapor deposition for thermal management in consumer electronics

Next-generation consumer electronics require excellent thermal management. Graphene is a good choice because its thermal conductivity is 13 times that of copper. Single-, bi- and few-layer graphene (SLG, BLG, FLG) with large sp2 domains were grown by rapid thermal processing chemical vapor deposition (RTP-CVD) from CH4 and H2 using Ar as the diluting gas. The quality of graphene was investigated by Raman spectroscopy and TEM. To demonstrate the heat dissipation capability of RTP-CVD-grown graphene, a 2 TB solid state drive was used and the temperature was measured by a FLIR thermal camera. Results indicate that high thermal conductivity graphene was prepared by diluting the precursor gas with Ar. SLG was prepared at a growth temperature of 1 000 °C and a time of 25 min. A transition from FLG to high-quality BLG was observed at low H2 concentrations. Using SLG, there was a 5 °C lower temperature rise than using a commercial copper heat dissipator. The heat dissipation ability of SLG was approximately 200 times that of commercial copper heat dissipators.

Terminal iterative learning control with an application to RTPCVD thickness control

A special type of iterative learning control (ILC) problem is considered. Due to the insufficient measurement capability in many real control problems such as Rapid Thermal Processing (RTP), it may happen that only the terminal output tracking error instead of the whole output trajectory tracking error is available. In the RTP chemical vapor deposition (CVD) of wafer fab. industry, the ultimate control objective is to control the deposition thickness (DT) at the end of the RTP cycle. The control profile for the next operation cycle has to be updated using the terminal DT tracking error alone. A revised ILC method is proposed to address this terminal output tracking problem. By parameterizing the control profile with a piecewise continuous functional basis, the parameters are updated by a high-order updating scheme. A convergence condition is obtained for a class of uncertain discrete-time time-varying linear systems including the RTPCVD system as the subset. Simulation results for an RTPCVD thickness control problem are presented to demonstrate the effectiveness of the proposed iterative learning scheme.

Application of neural fuzzy network to pyrometer correction and temperature control in rapid thermal processing

Temperature measurement and control are two difficult problems in the rapid thermal processing (RTP) system. For many applications such as rapid thermal processing chemical vapor deposition (RTCVD) and rapid thermal oxidation (RTO), large changes in wafer emissivity can occur during film growing, leading to erroneous temperature measurements with a single wavelength pyrometer. The error in the inferred temperature will affect the temperature control of the RTP system. In order to correct the temperature reading of the pyrometer, a neural fuzzy network is used to predict the emissivity changes for the compensation of measured temperature. As for the temperature control, to overcome ill performance of the temperature tracking system due to the inaccuracy of the identified model, another neural fuzzy network is used in the RTP system for learning inverse control simultaneously. The key advantage of neural fuzzy approach over traditional ones lies on that the approach does not require a mathematical description of the system while performing pyrometer correction and temperature control. Simulation results show that the adopted neural fuzzy networks can not only correct the pyrometer reading accurately, but also be able to track a temperature trajectory very well.

Brillouin scattering determination of the elastic constants in supported Ge films

Brillouin scattering from supported Ge films, prepared by rapid thermal processing chemical vapor deposition (RTPCVD) and plasma-enhanced chemical vapor deposition (PECVD) techniques, is carried out in the backscattering geometry. The phonon spectra are analyzed and simulated by taking the ripple and elasto-optic coupling into account, which leads to an accurate determination of the elastic constants. It is found that these constants are strongly dependent on deposition methods. In addition, we have also studied the influence of the interdiffusion in the interfacial layer on the elastic properties.

Epitaxial orientation of β-FeSi2/Si heterojunctions obtained by RTP chemical vapor deposition

In recent years the semiconducting phase of iron silicide 03B2-FeSi2 has attracted interest. Promising applications of a great deal of 03B2-FeSi2/Si heterojunctions are reported in semiconductor technology due to the 0.89 eV direct band gap of 03B2-FeSi2. Most of the papers devoted to this material present three different deposition modes, i.e. MBE, Solid Phase Epitaxy (SPE) and Reactive Deposition Epitaxy (RDE). The epitaxy of very thin layers of 03B2-FeSi2 has already been reported on (111) and (001) silicon substrates. This paper presents an original application of Chemical Vapor Deposition (CVD) for the growth of 03B2-FeSi2 using Rapid Thermal Processing (RTP). The results presented here mainly concern the epitaxial orientations and the morphology of 03B2-FeSi2 on silicon. The different epitaxial relationships are experimentally distinguished by the use of transmission electron diffraction (TED) and microscopy (TEM). Thick 03B2-FeSi2 layers (> 100 nm) have been selectively grown by RTP chemical vapor deposition on patterned (111) and (001) silicon wafers and under different experimental conditions. They are polycrystalline with large grains (about 1 03BCm) and mainly epitaxial. The main epitaxial relationship found is (220) 03B2-FeSi2 // (111) Si named type B in the literature. An important result is the flatness of the interface under each 03B2-FeSi2 grain which presents large areas (about 50 nm) without any monoatomic step. This result seems to be an advantage of the promising chemical vapor deposition process used which minimizes the interdiffusion processes at the interface.

Boron-enhanced low-temperature Si epitaxy by rapid thermal processing chemical vapor deposition

We demonstrate that epitaxial growth temperatures can be lowered by in situ boron incorporation using rapid thermal processing chemical vapor deposition (RTPCVD). Heavily boron-doped epitaxial layers with very abrupt dopant transition profiles have been grown at 800 °C. Carrier concentrations as high as 5×1019 cm−3 were obtained with defect densities of the order of 102–103 cm−2. The film quality and surface morphology were closely related to dopant concentration. Higher dopant concentrations improved surface morphology.

The rapid thermal processing chemical vapor deposition of silicon epitaxial films

The future of ultralarge-scale integration technology is tending toward reduced thermal processing to realize devices with higher integration densities and better performance. Rapid thermal processing chemical vapor deposition (RTPCVD) is a promising technology that can preserve the advantages of high-temperature processing without degrading the fidelity of junction profiles. Defect free, thin silicon epilayers with extremely abrupt dopant-transition profiles can be re-producibly grown by RTPCVD. Very high quality n-type and p-type heavily doped epilayers, using boron, arsenic, and phosphorus as dopants, have been grown by RTPCVD. Through superior process control and reduced thermal exposure, RTPCVD is expected to play an important part in the next generation of fabrication technology and in the development of novel silicon-based materials.

Defect Study of GeSi Alloy Multilayer Structures Grown by RTPCVD

We have grown multilayer structures of alternating and pure Si layers on (100) Si substrates by means of rapid thermal processing chemical vapor deposition (RTPCVD) at 900°C, using and as source gases and as a carrier gas. In strained layers, the only defects were Ge interstitial loops confined near the interface. In layers that were partially relaxed, misfit dislocations, stacking faults, and threading dislocations were observed. Ge pile‐up was also observed at the interface of relaxed layers containing high densities of threading dislocations.

Silicon Homoepitaxy by Rapid Thermal Processing Chemical Vapor Deposition (RTPCVD)—A Review

Rapid thermal processing chemical vapor deposition (RTPCVD) has received considerable attention because of its ability to reduce many of the processing problems associated with thermal exposure in conventional chemical vapor deposition, while still retaining the ability to grow high‐quality epitaxial layers. In this paper, silicon homoepitaxy growth by RTPCVD is studied extensively and comprehensively. The principles of the RTPCVD system are described, followed by results of experiments on in situ cleaning, undoped Si epitaxy on Si and silicon‐on‐insulator substrates, in situ doped Si epitaxy, and selective epitaxial growth of Si using oxide masks and oxide on polycrystalline Si on oxide masks. Selective growth was achieved without the use of . Our results show that RTPCVD is capable of growing high‐quality, epitaxial Si layers with sharp dopant transition profiles. A brief discussion of fabricated devices is included.

Si and GexSi1−x Epitaxial Growth on SOI Structures by Rapid Thermal Processing Chemical Vapor Deposition

AbstractA short time high temperature H2 pre-bake resulted in an undulating SIMOX surface, which planarized after epitaxial growth by rapid thermal processing chemical vapor deposition (RTPCVD). However, a short time, high temperature N2 pre-bake resulted in severe surface pitting. From dilute Schimmel etch results, no significant changes in the defect densities of the Si layers occurred after RTPCVD. Auger depth profiles of the SOI substrate prior to epitaxial growth show an oxygen peak in the SIMOX Si layer. However, the peak flattens out after epitaxial growth. Oxygen was not observed in the epitaxial film, even though oxygen was still observed in the SIMOX top Si layer.The use of GexSi1−x epitaxial layers to reduce threading dislocation densities was examined. A 1000°C Si buffer layer was first grown for 30s, followed by a GexSi1−x layer, and topped off by a 1000°C Si layer for 120s. The GexSi1−x layers were grown at temperatures varying from 850°C to 1000°C for 30s to 240s. The defect density was significantly reduced when the 900°C and 850°C GexSi1−x layers were used, although an increase in stacking fault densities (still small compared to threading dislocation densities) accompanied the lower deposition temperatures. The 1000°C GexSi1−x layer and a control sample in which pure Si was grown showed no significant decrease in defect densities.

Dopant Enhanced Low-Temperature Epitaxial Growth by Rapid Thermal Processing Chemical Vapor Deposition

ABSTRACTWe have demonstrated, for the first time, that the epitaxial growth temperature can be lowered by dopant incorporation using rapid thermal processing chemical vapor deposition (RTPCVD). Heavily arsenic-doped epitaxial layers with very abrupt dopant transition profiles and relative uniform carrier distribution have been achieved at 800°C. The defect formation is closely related to dopant concentration; the defect density as a function of carrier concentration shows a sharp transition at about 3×1018 cm−3.

Silicon epitaxial growth on silicon-on-insulator structures by rapid thermal processing chemical vapor deposition

We have used rapid thermal processing chemical vapor deposition (RTPCVD) for silicon epitaxial growth on silicon-on-insulator (SOI) substrates. The surface morphology of SOI rapid thermal annealed in different ambients was also examined. A short, high-temperature H2 anneal formed an undulating SOI surface, which planarized after RTPCVD. However, severe surface pitting was observed after a high-temperature N2 anneal. No significant changes in the defect density of the silicon layers occurred after RTPCVD and no stacking faults were observed in the epilayers.

Selective deposition of i n s i t u doped polycrystalline silicon by rapid thermal processing chemical vapor deposition

Selective polycrystalline silicon was successfully deposited and in situ doped wih arsenic for the first time by rapid thermal processing chemical vapor deposition (RTPCVD). The growth kinetics of SiH2Cl2/AsH3/H2 gas system have been studied by examining the dependence of growth rate on deposition temperature, volume percentage of SiH2Cl2, and AsH3 mole fraction. Submicron polycrystalline silicon layers with excellent selectivity and precise thickness control have been achieved with proper deposition conditions. The growth rate decreases as doping levels increase, and drastically decreases when the AsH3 mole fraction is higher. In addition, the growth rate is linearly proportional to the SiH2Cl2 flow rate for a fixed AsH3 flow rate.

Thin stacked oxide/nitride/oxide dielectrics formation by i n s i t u multiple reactive rapid thermal processing

Thin stacked SiO2/Si3N4/SiO2 (ONO) films have been fabricated for the first time using in situ multiple step rapid thermal processing chemical vapor deposition (RTP-CVD). Stacked Si3N4/SiO2 (NO) layers were deposited in situ by RTP-CVD. Some samples received an in situ rapid thermal oxidation immediately after stacked layer deposition to form oxide/nitride/oxide stacked layers. These films were characterized by ellipsometry, Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy, and Auger electron spectroscopy. Results show that well-defined Si3N4/SiO2 and Six Ny Oz /Si3N4/SiO2 stacked layers have been formed.

Growth of Thin Epitaxial Silicon Layers on Heavily Doped Substrates by RTP-CVD

ABSTRACTSilicon epitaxy plays an important role in improving the performance and reliability of semiconductor devices. The continuous scale-down in device feature size demands a low thermal budget epitaxial technique to maintain the structural integrity of processed devices. In this paper, rapid thermal processing chemical vapor deposition (RTP-CVD) has been used to deposit high quality, thin silicon epitaxial films with superior thickness control. Parameters affecting the quality and rate of epitaxial growth are discussed.

Formation of Ultrathin Stacked Dielectrics Prepared by In-Situ Multi-Step RTP-CVD

ABSTRACTUltrathin stacked SiO2/Si3N4/SiO2 films have been fabricated successfully using in-situ multi-step rapid thermal processing chemical vapor deposition (RTP-CVD). Stacked Si3N4/SiO2 (NO) layers were deposited first by RTP-CVD. Some samples were further rapid-thermal oxidized after stacked layer deposition to form oxide/nitride/oxide (ONO) stacked layers. Ellipsometry, Fourier transform infrared spectroscopy (FTIR), x-ray photoelectron spectroscopy (XPS), and Auger electron spectroscopy (AES) were performed to characterize the films. Results show that well defined stacked Si3N4/SiO2 layers were fabricated and for wafers subjected to rapid-thermal oxidation an oxygen-rich SixNyOz layer was formed on the top of the dielectric stack. Nitrogen pile-up at the dielectric/substrate interface was observed for all wafers indicating that nitrogen diffuses into the bottom oxide during nitride deposition even though the deposition temperature is well below those used in thermal nitridation of thermal oxides.