Rapid Thermal Low Pressure Chemical Vapor Deposition Research Articles

Optimization of Titanium Nitride Rapid Thermal CVD Process

Anomalous behavior during TiN growth through rapid thermal low-pressure chemical vapor deposition (RTLPCVD) from gas phase TiCl 4 -NH 3 -H 2 has been observed. Two deposition temperatures are used (500 °C and 800 °C) and two types of deposition process are defined (a long one-step process, and a multiple-step process). Resistivity, structure, composition, and growth behavior are examined and discussed in terms of oxygen contamination and classical nucleation theory. The long one-step process is better for mechanical applications, whereas the multiple-step process is more suitable for microelectronics.

Dépôt chimique en phase vapeur et à basse pression de couches minces à base de silicium dans un réacteur à lampes halogène

Low-pressure chemical vapor deposition (LPCVD) in halogen lamp-heated reactor (RTLPCVD: rapid thermal LPCVD) is a promising technique for silicon-based thin films deposition. Indeed, overall process time and gas consumption reduction in RTP reactors allows to project new device fabrication technologies (microsensors, solar cells) in order to reach a higher environmental safety with respect to classical technologies.Various gases available on our RTP installation (SiH4, NH3, N2O, O2, PH3, B2H6) enable several silicon-based thin films RTLPCVD deposition: intrinsic polycrystalline silicon (poly-Si) films or in situ doped poly-Si, silicon nitride (Si-N) and oxynitride (Si-O-N). In this paper, we discuss our results on deposition kinetics and physical properties of these thin films. It appeared that RTLPCVD silicon-based thin films with interesting structural, electrical, and optical properties can be synthesized in our lamp-heated reactor with a tight control of process parameters such as temperature, pressure, and gas flow ratios.

Structural and mechanical characterization of in-situ phosphorus-doped rapid transport low pressure chemical vapor deposition polycrystalline silicon films

Rapid thermal low pressure chemical vapor deposition (RTLPCVD) of in-situ phosphorus-doped (P-doped) polycrystalline silicon (poly-Si) thin films was carried out in a cold-wall rapid thermal processing reactor. Doping was obtained by adding phosphine (PH 3=200 ppm) gas to silane (SiH 4/Ar=10%) at a process pressure of 2 mbar and a deposition temperature in the 600°C–850°C range. Microstructural and micromechanical properties of the deposited layers were investigated by means of grazing X-Ray Diffraction. It appeared, particularly, that in-situ P-doping is responsible for a small-grained and relatively high stressed structure. However, a post-deposition rapid thermal annealing seems to be beneficial for suitable mechanical applications of in-situ P-doped RTLPCVD poly-Si films.

Growth and physical properties of in situ phosphorus-doped RTLPCVD polycrystalline silicon thin films

In situ phosphorus-doped (P-doped) polysilicon (poly-Si) thin films are obtained by rapid thermal low pressure chemical vapor deposition (RTLPCVD) in a single chamber RTP machine by using diluted silane (SiH 4/Ar=10%) and phosphine (PH 3=200 ppm). Deposition kinetics of poly-Si films were studied in the 600–850°C temperature range at fixed total pressure of 2 mbar and gas flow rate (100 sccm). Activation energy of 1.82 eV was calculated in the surface reaction deposition regime. Dopant activation has been obtained sequentially by RTO at 1000°C in pure O 2 atmosphere. This later process permits to both activate the phosphorus dopant and forms an ultrathin polyoxide which blocks dopant outdiffusion. Secondary ion-mass spectrometry (SIMS) analysis showed flat P-dopant profiles throughout the film thickness with a P concentration varying from 5.5×10 20 to 2.4×10 19 at/cm 3 when the deposition temperature increases in the 600–850°C range. Grazing incidence X-ray diffraction (XRD) has been used to study the structural properties of the poly-Si layers. It appeared particularly that the amorphous to crystalline temperature transition occurs at around 650°C. Finally, four-point probe measurements showed that sheet resitivities in the mΩ cm range can be routinely achieved for in situ P-doped RTLPCVD poly-Si films.

Low temperature rapid thermal low pressure chemical vapor deposition of 〈111〉 oriented TiN layers from the TiCl 4NH 3H 2 gaseous phase

Titanium nitride layers are deposited by Rapid Thermal Low-Pressure Chemical Vapor Deposition (RTLPCVD) from the TiCl 4NH 3H 2 gaseous phase. Growth rate, resistivity and crystallographic orientation are studied as a function of the deposition temperature and the NH 3/TiCl 4 partial pressures ratio called R. To fulfill the TiN barrier layer requirements, the deposition temperature and the R value have to be as low as possible. We show that with such conditions, the preferential orientation of the deposited TiN layer is always 〈200〉. This orientation enhances the 〈200〉 orientation of the aluminium overlayer which leads to poor electromigration resistance. In order to obtain 〈111〉 oriented TiN layer, a two step process is proposed. In this way, 〈111〉 oriented TiN layers are deposited at a deposition temperature and with an R ratio value as low as 500°C and 4, respectively. The resistivity of such as-deposited films is 200 μΩcm.

LPCVD SiO2 Layers Prepared from SiH4 and O2 at 450 °C in a Rapid Thermal Processing Reactor

In this paper experimental results of the silane oxidation kinetics in a rapid thermal low pressure chemical vapor deposition (RTLPCVD) cold wall reactor at 450 °C are presented. For a certain total pressure kept constant in the range of 0.6-4.5 mbar. it is always found a certain threshold silane partial pressure p(th) SiH4 (decreasing from 0.15 mbar to 0.076 mbar when the total pressure increases) which determines a sharp transition from no film formation to high deposition rates of the SiO 2 layers. Critical partial pressures for lower limits of explosion at room temperature (0.223 mbar) and at deposition temperature (0.17 mbar) are noticed. The film deposition is very sensitive to the changes in the chemical state of the walls. These results may indicate that the silane oxidation process is controlled by the gas phase chain reactions. By keeping constant the total pressure (4.5 mbar), the SiH 4 partial pressure (0.079 mbar) and the total gas flow rate (570 sccm), with the nitrogen varied as a gas balance, an increase-maximum-decrease dependence of deposition rate as a function of O 2 /SiH 4 mole ratio is found. Uniform SiO 2 layers ( 5% around the averaged value) were found for the above CVD conditions and an O 2 /SiH 4 ratio equal to 11. Without further process and equipment improvements this process cannot be used in practice.

Tungsten metallization onto InP prepared by rapid thermal low-pressure chemical vapor deposition of WF6 and H2

Tungsten (W) films were deposited onto InP in a cold wall, rapid thermal low-pressure chemical vapor deposition (RT-LPCVD) reactor, using a tungsten hexafluoride (WF6) gas reduced by hydrogen (H2). W films of thickness 50–450 nm were deposited in the temperature range of 350–550 °C, pressure range of 0.5–4.5 Torr, and deposition rates up to 4 nm/s with an apparent activation energy of about 1.12 eV. The film stress varied depending on the deposition pressure, from low compressive (deposition at 0.5 Torr) to moderate tensile (deposition at about 4.5 Torr). Post-deposition sintering of the W films at temperatures up to 600 °C led to reduction of the resistivity with a minimum value of about 55 μΩ cm as a result of heating at 500 °C.

Low resistance tungsten films on GaAs deposited by means of rapid thermal low pressure chemical vapor deposition

Low resistance tungsten (W) films were deposited onto GaAs substrates by means of rapid thermal low pressure chemical vapor deposition (RT-LPCVD), using tungsten hexafluoride (WF6) gas reduced by hydrogen (H2). Deposition temperatures up to 550 °C for durations of up to 30 s were explored, resulting in deposition of relatively pure W films (containing less than 2% O2 and C). Post-deposition sintering of the layers led to significant reduction of the resistivity to values as low as 50 μΩ cm. The efficiency of the deposition improved upon increasing the H2 flow rate up to 1250 sccm resulting in a deposition rate of about 10 nm/s at a total chamber pressure of 3.5 Torr and temperature of 500 °C. The films appeared to be polycrystalline with a very fine grain structure, regardless of the deposition temperature with good morphology and underwent a limited reaction with the underlying GaAs substrates.

W and Related Alloys Deposited onto InP by RT-LPCVD

ABSTRACTTungsten (W) films were deposited onto InP in a cold wall, rapid thermal low-pressure chemical vapor deposition (RT-LPCVD) reactor, from a tungsten hexafluoride (WF6) gas reduced by hydrogran (H2). W films of thickness 50 to 450 nm were deposited in the temperature range of 350° to 550°C, pressure range of 0.5 to 4.5 Torr and deposition rates up to 4 nm/sec with an apparent activation energy of about 1.12 eV. The film stress varied depending upon the deposition pressure, from low compressive for deposition at 0.5 Torr to moderate tensile for deposition at about 4.5 Torr. The films were aged at temperatures as high as 300°C for about 800 hr and exhibited an excellent mechanical stability. Post-deposition sintering of the W films at temperatures up to 600°C led to reduction of the resistivity with a minimum value of about 55μΩ-crn as a result of heating at 500°C. Conditions for both selective and blanket deposition were defined, and a dry etching process for further geometrical definitions of the films was developed, providing etch rates of 40 to 50 nm·sec-1. This report reflects the first attempt to deposit W films onto III-V semiconductor at a very high rate by means of RT-LPCVD.

Highly stable silicon dioxide films deposited by means of rapid thermal low-pressure chemical vapor deposition onto InP

An attempt was made to deposit a high thermally stable silicon dioxide (SiO2) film onto InP substrates. The films were grown by rapid thermal, low-pressure chemical vapor deposition (RT-LPCVD), using pure oxygen (O2) and 2% diluted silane (SiH4) in argon (Ar) gas sources, in the temperature range of 350–550 °C and pressure range of 3–10 Torr. The SiO2/InP structures were heated, post-deposition, up to 1000 °C for durations of up to 5 min, resulting in negligible changes in the properties of the SiO2 films and a limited SiO2/InP interfacial reaction of about 15 nm thick. The higher the initial deposition temperature of the SiO2 the larger was the film compressive stress and the less the degree of densification the film underwent through the post-deposition heating cycles.

Rapid Growth Kinetics, Mechanical Properties and Thermal Stability of Siox Thin Films Grown by Rapid Thermal Low Pressure Chemical Vapor Deposition

ABSTRACTHigh quality SiOx films were deposited onto InP substrates in the temperature range of 350 to 550°C and pressure range of 5 to 15 Torr. Depositions were made by means of rapid thermal low pressure chemical vapor deposition (RT-LPCVD) using oxygen (O2) and 2% diluted silane (SiH4) in argon (Ar) gas sources, with O2:SiH4 gas ratio of 5:1 to 50:1. High deposition rates of 15–50 nm/sec were obtained, providing uniform SiOx layers, with low stresses of −5×109 to −2×109 dyne-cm−2, and thermal stability on post deposition temperatures up to 1000°C. The SiOx films had refractive indexes between 1.44 and 1.50, densities of 2.25 to 2.37grcm−3 and exhibited wet etch rates of 0.2 to 0.8 nmsec.−1 through standard p-etch process. The influence of the various process parameters on the SiOx film properties was examined.