Plasma-enhanced Chemical Vapor Deposition Reactor Research Articles

Development of n-Type, Passivating Nanocrystalline Silicon Oxide Films via Plasma-Enhanced Chemical Vapor Deposition

Nanocrystalline silicon oxide (nc-SiOx:H) is a multipurpose material with varied applications in solar cells as a transparent front contact, intermediate reflector, back reflector layer, and even tunnel layer for passivating contacts, owing to the easy tailoring of its optical properties. In this work, we systematically investigate the influence of the gas mixture (SiH4, CO2, PH3, and H2), RF power, and process pressure on the optical, structural, and passivation properties of thin n-type nc-SiOx:H films prepared in an industrial, high-throughput, plasma-enhanced chemical vapor deposition (PECVD) reactor. We provide a detailed description of the n-type nc-SiOx:H material development using various structural and optical characterization techniques (scanning electron microscopy (SEM), energy dispersive X-ray (EDX), Raman spectroscopy, and spectroscopic ellipsometry) with a focus on the relationship between the material properties and the passivation they provide to n-type c-Si wafers characterized by their effective carrier lifetime (τeff). Furthermore, we also outline the parameters to be kept in mind while developing different n-type nc-SiOx:H layers for different solar cell applications. We report a tunable optical gap (1.8–2.3 eV) for our n-type nc-SiOx:H films as well as excellent passivation properties with a τeff of up to 4.1 ms (implied open-circuit voltage (iVoc)~715 mV) before annealing. Oxygen content plays an important role in determining the crystallinity and hence passivation quality of the deposited nanocrystalline silicon oxide films.

Mechanical and optical properties of amorphous silicon nitride-based films prepared by electron cyclotron resonance plasma-enhanced chemical vapor deposition

Silicon nitride (SiNx) based films have been recognized as essential dielectric films in the microelectronics and optoelectronics industry due to their desirable properties, such as high electrical insulation, excellent thermal stability, and compatibility with integrated circuit fabrication processes. They are also a potential candidate for fabricating wavelength-selective reflective coatings and surface passivation layers in building-integrated photovoltaics technologies. SiNx-based films are one of the popular choices for antireflective coatings in photovoltaics as well. Recently, SiNx and oxynitride (SiOyNx) based thin film optical filters have been explored to provide distinct color rendering to solar-charged electrical vehicles. Since solar cells have a lifespan of many years and the coating surfaces are substantial, it is essential to produce films with controlled optical and mechanical properties and maintain mechanical integrity against corrosion and wear. This study aims to design a deposition process and optimize minimal parameters for stable plasma conditions during multilayer deposition of SiNx and SiOyNx films using an electron cyclotron resonance plasma-enhanced chemical vapor deposition reactor with SiH4/N2/O2/Ar precursor mixtures at 120 °C. The primary goal was to investigate the influence of gas flow adjustments on the optical and mechanical properties, specifically targeting the refractive index and mechanical properties of the films. We measured the refractive index and the absorption of the films using variable angle spectroscopic ellipsometry. Then, we evaluated the mechanical residual stress ex situ using the wafer curvature measurement method. We have determined the elastic modulus and the hardness of the films using nanoindentation. The experimental results have shown a significant dependence of the optical and mechanical properties on the deposition parameters. To investigate the factors contributing to the intrinsic mechanical stress and to better understand SiNx film degradation mechanisms, we have studied the effect of postdeposition thermal cycling on the properties of the films. Several thermal-cycling experiments from room temperature to 400 °C were performed on different SiNx films, and the results showed an irreversible variation of the mechanical stress toward the tensile stresses caused by delamination of the films, while the refractive index remained unchanged.

1,4-Bis(trimethylsilyl)piperazine—Thermal Properties and Application as CVD Precursor

We report an investigation into 1,4-Bis-N,N-(trimethylsilyl)piperazine (BTMSP) as a novel precursor for the synthesis of silicon carbonitride films by chemical vapor deposition (CVD). The thermal stability, temperature dependence of vapor pressure and thermodynamic constants of the evaporation process of BTMSP were determined by static tensimetry with a glass membrane zero manometer. The transformation of the compound in low-power (25 W) plasma conditions was investigated by optical emission spectroscopy. It was shown that BTMSP undergoes destruction, accompanied by H and CH elimination and CN formation. SiCN(H) films were deposited in a hot-wall plasma-enhanced CVD reactor. The optical properties of the films were studied by spectral ellipsometry (refractive index: 1.5–2.2; absorption coefficient: 0–0.12) and UV–Vis spectroscopy (transmittance: up to 95%; optical bandgap: 1.6–4.9 eV). Information on the aging behavior of the films is also provided. The transformation of the films occurred through water adsorption and the formation of Si–O bonds with the degradation of Si–H, N–H and Si–CHx–Si bonds.

Design and fabrication of color-generating nitride based thin-film optical filters for photovoltaic applications

In this paper, we present the design and fabrication of a 11-layer notch filter for photovoltaic applications. Thickness modulation has been done on a starting quarter-wave design to obtain a 11-layer final structure. For our design parameters, we considered materials with indices of 2.09 and 1.51 as high and low refractive index materials, respectively. Since this filter aims for photovoltaic applications, we defined the substrate as silicon. The design shows a reflection peak of around 73% from 350 to 467 nm with a FWHM of 79 nm along with less than 10% reflection for longer wavelengths of the remaining high transmission region of 300–1200 nm. For fabrication, we used silicon nitride and silicon oxynitride as alternating high and low refractive index materials on a silicon substrate. Layers of silicon nitride and oxynitride were deposited with an electron cyclotron resonance plasma-enhanced chemical vapor deposition reactor and characterized with variable angle spectroscopic ellipsometry and spectrophotometry.

The influence of droplet-based seeding of nanodiamond particles on the morphological, optical, and mechanical properties of diamond coatings on glass

This work investigates four different methods for the seeding of nanodiamond (ND) particles towards applying nanocrystalline diamond coatings on glass. The standard spin coating and dip coating are investigated together with two droplet-based techniques, ink-jet printing and ultrasonic spray coating (USSC). The application of these last two techniques for diamond coatings on glass is novel and is specifically designed for patterning and large area deposition, respectively. Comparing the seeding processes, their impact on the chemical vapor deposited nanocrystalline diamond (NCD) layers is unclear. Here, particularly the impact on the morphological, optical, and mechanical properties, are studied. In this work, borosilicate glass substrates were seeded, after which diamond layers were grown in a linear antenna microwave plasma-enhanced chemical vapor deposition reactor to thicknesses of 45, 100, and 500 nm. The coatings showed a roughness that is 2 to 3 times higher for the droplet-based seeding techniques compared to spin coating. It was found that the optical absorption coefficient for 100 nm thick samples prepared using USSC was 2400 cm−1 at the wavelength of 550 nm, compared to 1500 cm- 1 using spin and dip seeding techniques. The stress in the film was compressive as determined by curvature measurements. Sand-trickling tests on samples coated with 100 nm thick diamond films showed similar resistance against damaging for all seeding techniques without delamination. Therefore, the different techniques achieve mechanically competitive performance. On top USSC and ink-jet printing have the opportunity to fully cover substrates on large-scale flat and even 3D surfaces, or pattern fine structures, which is not possible for standard spin and dip coating. It can be concluded that diamond coatings on large glass plates for scratch resistance, and sensing due their somewhat higher roughness, are within reach using these innovative droplet-based seeding technologies.

Ultrahigh Incorporation of Tin in SiSn Nanowires Grown via In-Plane Solid-Liquid-Solid Mechanism

We report on the growth of sn-catalyzed in-plane silicon nanowires (SiNWs) using the solid–liquid-solid (SLS) mechanism and their application to nano-electronics. The in-plane SLS growth process allows us to obtain very high tin concentrations ∼ 10 at.% (more than 1000 times the expected concentration from the phase diagram). The growth is achieved in a plasma-enhanced chemical vapor deposition reactor, in a single pump-down process. Atom probe tomography (APT) and transmission electron microscopy (TEM) are used to assess the composition of these SiSn NWs. The atomic-scale investigation shows that Sn atoms are similarly distributed in crystalline SiSn NWs grown at 300 °C and 400 °C, with different sn-enrichments along structural defects. A NW-based field-effect transistor (FET) is fabricated in which a SiSn NW is implemented as the channel for charge transport, reaching a field effect hole mobility of 80 cm2/V.s.

In situ minority carrier lifetime via fast modulated photoluminescence

Modulated photoluminescence (MPL) is a powerful technique for determining the effective minority carrier lifetime (τeff) of semiconductor materials and devices. MPL is based on the measurement of phase shifts between two sinusoidal waves (minimal amplitude excitation; and PL signal). In particular, in situ τeff has been proven to be an effective measurement at showing changes within a plasma-enhanced chemical vapor deposition reactor during fabrication of c-Si solar cells. However, the required time for a single measurement, using the previous method, was 40 s. In this paper a new input signal is proposed, called Dolphin's Wave, providing a method for decreasing the required measurement period to under 2 s, using superposition, frequency sweeps, and wavelets.

Chlorine-Assisted Growth of Epitaxial InGaN and AlGaN Crystals at Low Temperatures Using Plasma-Enhanced Chemical Vapor Deposition

The chlorine-assisted growth of epitaxial indium gallium nitride (InGaN) and aluminum gallium nitride (AlGaN) crystals was achieved with high reproducibility at the low temperature of 600 °C in the plasma-enhanced chemical vapor deposition (PECVD) reactor via the reaction between the metal trichlorides with high vapor pressures and nitrogen plasma. After adding hydrogen gas to the growth processes of InGaN and AlGaN, the problems for the etching of chlorine plasma on the as-grown InGaN crystals and the appearance of crystal planes different from (002), derived from the worse and the better bonding abilities of materials, respectively, were solved effectively. Inside AlGaN crystals, the phase separation of gallium nitride (GaN) and aluminum nitride (AlN) can be avoided by controlling the amount of precursor aluminum. The epitaxial InGaN and AlGaN crystals have the same (002) crystal plane as the GaN(002) bottom layers and exhibit the same ⟨0001⟩ crystallographic growth direction along the axial direction of GaN microrods, representing the consistent growth orientation of the epitaxial crystals. The process temperatures of InGaN and AlGaN can be greatly decreased using chlorine gas and plasma so that the related applications of low-temperature growth may be expanded drastically in the future.

PECVD Silicon Nitride-Based Multilayers with Optimized Mechanical Properties

Silicon nitride (SiN) based films deposited by plasma-enhanced chemical vapor deposition (PECVD) have interesting optical, mechanical, and chemical properties. They are used for applications such as anti-reflective coatings and surface passivation layers in solar cells. Amorphous SiN-based films also are frequently used to create multilayer structures of alternatingly high-index and low-index films. This approach is very promising to fabricate narrow-bandwidth notch filters on photovoltaic cells to reflect on demand a wide variety of colors over the entire visible spectrum [1]. However, these multilayer structures need to be highly durable and mechanically stable since the lifecycle of photovoltaic cells in some applications [2] is very long, and the coated surfaces are very large. To satisfy these specific functional requirements, we need to adjust the films' optical and mechanical properties by changing the deposition parameters of a PECVD reactor. For instance, it is possible to strongly influence the chemical composition of amorphous SiN-based films, such as their stoichiometry, by tuning the gas flows [3]. This work investigates the effect of the deposition pressure, power, and source gas ratio on SiN-based monolayers during plasma deposition. We have deposited SiN and silicon oxynitride (SiON) films in an electron cyclotron resonance (ECR) PECVD reactor using a SiH4/N2/O2/Ar precursor mixture. We have measured the refractive index and the absorption of the films using a variable angle spectroscopic ellipsometry (VASE) to assess their optical quality. The mechanical properties of the films, such as residual stress and coefficient of thermal expansion, were measured ex-situ on a KLA-Tencor FLX-2320 film stress measurement system. The Young's modulus and hardness of the films were evaluated using nanoindentation. After studying the properties of monolayers, we have made numerical simulations and further characterizations to optimize the design of multilayer structures considering both the optical and mechanical properties. Through this discussion, we try to better understand the interactions taking place when amorphous SiN-based films with different structural properties and compositions are stacked on top of each other. Finally, we suggest methods to predict and control the residual stress in multilayer structures without affecting the optical properties.

Strain engineering in III-V photonic components through structuration of SiNx films

We describe work to quantify the effects of structured dielectric thin films, such as SiNx, at the surface of III-V semiconductors, in terms of strain engineering with applications to photonic components such as waveguides and lasers. We show that the strain in the semiconductor can be engineered by controlling the stress in the dielectric thin film by tuning its deposition process. In the first part of this study, we describe how we can control the amount of this built-in mechanical stress, in the case of SiNx, over a large range, from highly tensile (300 MPa) to highly compressive (−800 MPa), using two different kinds of plasma-enhanced chemical vapor deposition reactors: a standard capacitively coupled reactor with radiofrequency excitation and an electron cyclotron resonance reactor with microwave excitation. We focused on characterizing and understanding these thin films' optical and chemical bonding properties through spectroscopic ellipsometry and Fourier transform infrared spectroscopy. We have also studied their mechanical properties experimentally using the wafer curvature measurement technique, microstructure fabrication, and nanoindentation measurements. In the second part, we show accurate measurements of the strain distribution induced within GaAs wafers when such thin films are structured in the shape of elongated stripes of variable width, using standard optical lithography and plasma etching. For this, we map the anisotropic deformation, measuring the degree of polarization of the spectrally integrated photoluminescence (PL) generated within GaAs by excitation with a red laser. PL from the bulk cubic semiconductors such as GaAs and InP is unpolarized, whereas anisotropic strain produces some degree of polarization. These maps were measured either from the semiconductor surface or from cleaved cross sections. They provide a detailed and complete image of the crystal deformation in the vicinity of the structured stressor film. Finally, we have performed some finite element simulations trying to reproduce the experimental maps. This investigation covering the different steps, including control of the built-in stress within the SiNx thin films, mapping of the anisotropic deformation field generated within the semiconductor beneath the structured films, and numerical simulation of these effects, allows us to propose a set of recipes that can be employed for strain engineering of III-V photonic components. Our simulation scheme is helpful for the design of the photonic components, e.g., to predict the local changes in the refractive index due to the photoelastic effect.

Room Temperature Growth of Silica Nanowires on Top of Ultrathin Si Nanowires Synthesized with Sn‐Cu Bimetallic Seeds

Si nanowires (NWs) are grown by the vapor–liquid–solid method using Cu–Sn bimetallic catalysts in a plasma‐enhanced chemical vapor deposition (PECVD) reactor. The microstructure of the NWs is analyzed by transmission electron microscopy and energy‐dispersive X‐ray spectroscopy. An amorphous SiO2 region, much larger than the native oxide, is present on top of each crystalline SiNW: in SiNWs with diameter below 10 nm, it takes the form of a silica NW of up to 50 nm in length. The new NW separates the initial catalyst particle into one that stays in contact with the SiNW and one or more that lies at the top of the new NW. The former is made of Cu and Cu3Si and contains no Sn, whereas the latter keeps amounts of both elements. The observed microstructure appears to be the result of a mechanism of Si oxidation catalyzed by Cu3Si. The deposit after SiNW growth, in the PECVD reactor, of a protecting 2 nm thick layer of hydrogenated amorphous Si, completely suppresses this mechanism. Reference for future applications based on Cu–Sn‐catalyzed quantum‐sized SiNWs is provided.

Distribution of the Deposition Rates in an Industrial-Size PECVD Reactor Using HMDSO Precursor

The deposition rates of protective coatings resembling polydimethylsiloxane (PDMS) were measured with numerous sensors placed at different positions on the walls of a plasma-enhanced chemical vapor deposition (PECVD) reactor with a volume of approximately 5 m3. The plasma was maintained by an asymmetric capacitively coupled radiofrequency (RF) discharge using a generator with a frequency 40 kHz and an adjustable power of up to 8 kW. Hexamethyldisiloxane (HMDSO) was leaked into the reactor at 130 sccm with continuous pumping using roots pumps with a nominal pumping speed of 8800 m3 h−1 backed by rotary pumps with a nominal pumping speed of 1260 m3 h−1. Deposition rates were measured versus the discharge power in an empty reactor and a reactor loaded with samples. The highest deposition rate of approximately 15 nm min–1 was observed in an empty reactor close to the powered electrodes and the lowest of approximately 1 nm min–1 was observed close to the precursor inlet. The deposition rate was about an order of magnitude lower if the reactor was fully loaded with the samples, and the ratio between deposition rates in an empty reactor and loaded reactor was the largest far from the powered electrodes. The results were explained by the loss of plasma radicals on the surfaces of the materials facing the plasma and by the peculiarities of the gas-phase reactions typical for asymmetric RF discharges.

High Density of Quantum-Sized Silicon Nanowires with Different Polytypes Grown with Bimetallic Catalysts.

When Si nanowires (NWs) have diameters below about 10 nm, their band gap increases as their diameter decreases; moreover, it can be direct if the material adopts the metastable diamond hexagonal structure. To prepare such wires, we have developed an original variant of the vapor–liquid–solid process based on the use of a bimetallic Cu–Sn catalyst in a plasma-enhanced chemical vapor deposition reactor, which allows us to prevent droplets from coalescing and favors the growth of a high density of NWs with a narrow diameter distribution. Controlling the deposited thickness of the catalyst materials at the sub-nanometer level allows us to get dense arrays (up to 6 × 1010 cm–2) of very-small-diameter NWs of 6 nm on average (standard deviation of 1.6 nm) with crystalline cores of about 4 nm. The transmission electron microscopy analysis shows that both 3C and 2H polytypes are present, with the 2H hexagonal diamond structure appearing in 5–13% of the analyzed NWs per sample.

Characterising a Custom-Built Radio Frequency PECVD Reactor to Vary the Mechanical Properties of TMDSO Films.

Plasma-polymerised tetramethyldisiloxane (TMDSO) films are frequently applied as coatings for their abrasion resistance and barrier properties. By manipulating the deposition parameters, the chemical structure and thus mechanical properties of the films can also be controlled. These mechanical properties make them attractive as energy adsorbing layers for a range of applications, including carbon fibre composites. In this study, a new radio frequency (RF) plasma-enhanced chemical vapour deposition (PECVD) plasma reactor was designed with the capability to coat fibres with an energy adsorbing film. A key characterisation step for the system was establishing how the properties of the TMDSO films could be modified and compared with those deposited using a well-characterized microwave (MW) PECVD reactor. Film thickness and chemistry were determined with ellipsometry and X-ray photoelectron spectroscopy, respectively. The mechanical properties were investigated by nanoindentation and atomic force microscopy with peak-force quantitative nanomechanical mapping. The RF PECVD films had a greater range of Young’s modulus and hardness values than the MW PECVD films, with values as high as 56.4 GPa and 7.5 GPa, respectively. These results demonstrated the varied properties of TMDSO films that could in turn be deposited onto carbon fibres using a custom-built RF PECVD reactor.

Tin reduction from fluorine doped tin oxide for silicon nanowire-based solar energy harvesting and storage.

Hydrogen plasma reduction of fluorine doped tin oxide is a beneficial method to form tin nanodroplets on the sample surface directly in the plasma-enhanced chemical vapor deposition reactor. The formation of catalyst droplets is a crucial initial step for vapor-liquid-solid growth of silicon nanowires for radial junction solar cells and solar fuel cell technology. We present an original optical model which allows us to trace the formation process on fluorine doped tin oxide on soda-lime glass substrate from the in situ data and is in a good agreement with the spectroscopic ellipsometry data measured before and during the reduction process. The model reproduces well the phase shift introduced by a transition double layer in fluorine doped tin oxide which acts as a barrier against the sodium diffusion. Furthermore, we study the process of tin reduction from fluorine doped tin oxide in a real time and compare estimated amount of produced metallic tin with images from scanning electron microscopy.The proposed approach is very important for in situ real-time monitoring of the one-pump-down fabrication process used to grow nanowires and form radial junction devices.

A COMPREHENSIVE REVIEW ON THIN FILM DEPOSITIONS ON PECVD REACTORS

The deposition of thin films by Plasma Enhanced Chemical Vapor Deposition (PECVD) method is a critical process in the fabrication of MEMS or semiconductor devices. The current paper presents an comprehensive overview of PECVD process. After a short description of the PECVD reactors main layers and their application such as silicon oxide, TEOS, silicon nitride, silicon oxynitride, silicon carbide, amorphous silicon, diamond like carbon are presented. The influence of the process parameters such as: chamber pressure, substrate temperature, mass flow rate, RF Power and RF Power mode on deposition rate, film thickness uniformity, refractive index uniformity and film stress were analysed. The main challenge of thin films PECVD deposition for Microelectromechanical Systems (MEMS)and semiconductor devices is to optimize the deposition parameters for high deposition rate with low film stress which and if is possible at low deposition temperature.

The effects of carbon incorporation on the refractive index of PECVD silicon oxide layers

Silicon oxide (SiOx) has many applications, including as a low-refractive index material. Plasma enhanced chemical vapor deposition (PECVD) processes are facile, low temperature routes to produce thin SiOx layers. A route to decrease the refractive index of SiOx films is to increase the layer porosity although maintaining structural and optical stability remains challenging. Organic carbon-containing sacrificial layers have been shown to modify the growth and resulting structure of PECVD SiOx layers. In this work, we study the effect of adding methane (CH4) to the standard SiOx process gas mixture (silane and nitrous oxide) and varying deposition temperatures and microwave power in an industrial-scale, microwave PECVD reactor. Spectral ellipsometry was used to measure the optical properties of deposited layers, Fourier-transformed infrared (FTIR) spectroscopy to determine bonding and the layer porosity, and optical emission spectroscopy to characterize the plasma. We propose two regimes characterized by whether adding CH4 increases or decreases the refractive index and porosity of deposited layers compared to SiOx layers grown under standard conditions. However, the magnitude of the effect of adding CH4 was not large and would not find industrial application. Furthermore, the deposited layers’ refractive indices increased over time, indicating that the effects of adding CH4 to the process gas mixture were not stable. To help explain our results and to provide guidance for future efforts to better control the refractive index of PECVD SiOx layers via carbon incorporation while maintaining layer stability, we propose possible growth pathways for our layers considering both plasma reactions and surface processes.

Phase Transformation of Nanocrystalline Diamond Films: Effect of Methane Concentration

Ultra-nanocrystalline diamond films were prepared by a microwave plasma-enhanced chemical vapor deposition reactor using CH4/H2 gas mixture with a power as low as 650 W. The effects of CH4 concentration on nanostructure of the films and gas-phase species in plasma were investigated. The CH4 concentrations of 1.5%, 3.0%, 3.5%, and 4.0% were used and balanced with H2 to a total flow rate of 200 sccm. Morphology and composition of the films were characterized by SEM, Raman spectroscopy and Auger spectroscopy. The gas-phase species and electron density in the plasma were explored by optical emission spectroscopy and plasma-impedance measurement. The increasing CH4 concentration from 1.5% to 4.0% increased C2Hx species and decreased electron density. Phase of the film transform from nano- into ultranano- diamond phase but the growth rate revealingly decreased from 300 to 210 nm/h. Raman spectra indicate the higher CH4 concentration promted phase of the film transiton from NCD to UNCD. While Auger spectra revealed that UNCD film deposited with 4.0%CH4 was composed of 90.52% diamond phase but only 9.48% of graphite phase. The relation between phase transformation of the films and growth mechnism controlled by gas-phase species in the plasma will be dissused.

Growth of SiGeSn Thin Films Using Simplified PECVD Reactor towards NIR Sensor Devices

SiGeSn is a promising group IV semiconducting alloy to advance the field of silicon photonics. The bandgap of the alloy can be tuned by varying its’ Si and Sn concentrations for developing devices in the near infrared (NIR) range. The growth of the material using a cost-effective process is still challenging due to various obstacles. In this work, a simplified in-house assembled plasma enhanced chemical vapor deposition (PECVD) reactor was used to deposit SiGeSn films. Plasma allows for the use of commercially available precursors (GeH4, Si2H6 and SnCl4) while providing high dissociation and deposition growth rates. Polycrystalline films were deposited at susceptor temperatures in the range of 350 °C–450 °C to study the effect of process temperature on the Sn segregation and Sn incorporation in the films. Selective area growth (SAG) of SiGeSn films was also achieved by depositing films on patterned silicon substrates. The composition of the films was characterized by Rutherford Back Scattering while the structural and optical properties of the films were analyzed using X-ray diffraction and Raman spectroscopy. Selectively grown films were fabricated into basic test photodiodes and evaluated for electrical performance under NIR illumination.

PECVD Growth of Composition Graded SiGeSn Thin Films as Novel Approach to Limit Tin Segregation

SiGeSn is a promising group IV material to develop the field of silicon photonics. Increasing the tin concentration in the alloy is desired in order to achieve a direct bandgap in the material. This necessitates low temperature growth and proper strain management in the films during growth to prevent tin segregation. In this work, plasma enhanced chemical vapor deposition (PECVD) was used to grow composition graded SiGeSn films at low processing temperatures of 350 °C–380 °C using a simplified PECVD reactor. Polycrystalline films were deposited using a multi-step approach to prevent tin phase separation at higher Sn concentrations by alleviating the strain arising from the incorporation of Sn in the film lattice. Rutherford Back Scattering measurements indicated that films with Sn content of up to 8% without any Sn phase segregation were achieved. The structural and optical properties of the films were analyzed using X-ray diffraction and Raman spectroscopy.