Polycrystalline 3C-SiC Thin Films Research Articles

Impact of alternating precursor supply and gas flow on the LPCVD growth behavior of polycrystalline 3C-SiC thin films on Si

In this paper, we will provide information on the growth mechanism of 3C-SiC using alternating supply deposition (ASD). SiH4 and C3H8 were introduced successively in a low-pressure chemical vapor deposition (LPCVD) system at 1000 °C, forming a stoichiometric polycrystalline 3C-SiC thin film on Si substrates. We demonstrate the influence of different gas flow rates on thin film properties. In detail, altering the flow rates of the precursors and the carrier gas resulted in changes of the growth rate, the surface roughness, the crystal growth mechanisms as well as the crystal quality. Hydrogen inhibition and passivation are proposed to be the main effects influencing the growth behavior of ASD thin films. Applying ASD to grow 3C-SiC thin films with precursors from low to high flow rates resulted in a transition of different growth mechanisms influencing the surface roughness and grain size. Furthermore, we could prove that ASD is a cyclic step-by-step carbon-assisted redistribution of a prior deposited silicon film. This is shown by contact angle measurements of three differently terminated surfaces during the specific phases of one ASD cycle. High resolution transmission electron microscopy (HRTEM) analysis showed a continuous and homogenous thin film and confirmed the absence of silicon- or carbon-rich layers. ASD enables 3C-SiC thin films with customized properties for tailored micro electromechanical system (MEMS) applications.

Seebeck Coefficient of Heavily Doped Polycrystalline 3C-SiC Deposited by LPCVD

The Seebeck coefficient of heavily-nitrogen-doped n-type polycrystalline 3C-SiC (n-SiC) and platinum (Pt) thin films has been measured from room temperature up to 300 °C by using a microfabricated test structure. At room temperature, the absolute Seebeck coefficient of the n-SiC is -10 μV/°C. With ambient temperature increase, the absolute Seebeck coefficient of the n-SiC is found to gradually increase, reaching -20 μV/°C at 300 °C.

Effects of In-situ Doping on the Electrical and the Optical Characteristics of Anodized Polycrystalline 3C-SiC Thin Films Fabricated Using Chemical Vapor Deposition with a Single Precursor of Hexamethyldisilane

Effects of In-situ Doping on the Electrical and the Optical Characteristics of Anodized Polycrystalline 3C-SiC Thin Films Fabricated Using Chemical Vapor Deposition with a Single Precursor of Hexamethyldisilane

Characteristics of Anodized Polycrystalline 3C-SiC Thin Films Deposited by Using Chemical Vapor Deposition with Single-precursor Hexamethyldisilane for Different In-situ-doping Concentrations

Characteristics of Anodized Polycrystalline 3C-SiC Thin Films Deposited by Using Chemical Vapor Deposition with Single-precursor Hexamethyldisilane for Different In-situ-doping Concentrations

In-situ 도핑량이 다공성 3C-SiC 박막의 특성에 미치는 영향

This paper describes the elecrtical and optical characteristics of <TEX>$N_2$</TEX> doped porous 3C-SiC films. Polycrystalline 3C-SiC thin films are anodized by <TEX>$HF+C_2H_5OH$</TEX> solution with UV-LED exposure. The growth of in-situ doped 3C-SiC thin films on p-type Si (100) wafers is carried out by using APCVD (atmospheric pressure chemical vapor deposition) with a single-precursor of HMDS (hexamethyildisilane: <TEX>$Si_2(CH_3)_6)$</TEX>. 0 ~ 40 sccm <TEX>$N_2$</TEX> was used for doping. After the growth of doped 3C-SiC, porous 3C-SiC is formed by anodization with <TEX>$7.1\;mA/cm^2$</TEX> current density for anodization time of 60 sec. The average pore diameter is about 30 nm, and etched area is increased with <TEX>$N_2$</TEX> doping rate. These results are attributed to the decrease of crystallinity by <TEX>$N_2$</TEX> doping. Mobility is dramatically decreased in porous 3C-SiC. The band gaps of polycrystalline 3C-SiC films and doped porous 3C-SiC are 2.5 eV and 2.7 eV, respectively.

SiC 마이크로 히터가 내장된 극한 환경용 NO 센서의 제작과 특성

This paper describes the fabrication and characteristics of a NO sensor using ZnO thin film integrated 3C-SiC micro heater based on polycrystalline 3C-SiC thin film of operation in harsh environments. The sensitivity, response time, and operating properties in high temperature and voltages of NO sensors based SiC MEMS are measured and analyzed. The sensitivity of device with pure ZnO thin film at the heater operating power of 13.5 mW (<TEX>$300^{\circ}C$</TEX>) is 0.875 in NO gas concentration of 0.046 ppm. In the case of Pt doping, the sensitivity of at power consumption of 5.9 mW (<TEX>$250^{\circ}C$</TEX>) was 1.92 at same gas flow rate. The ZnO with doped Pt was showed higher sensitivity, lower working temperature and faster adsorption characteristics to NO gas than pure ZnO thin film. The NO gas sensor integrated SiC micro heater is more strength than others in high voltage and temperature environments.

Characteristics of Porous 3C-SiC Thin Films Formed with Nitrogen Doping Concentrations

This paper describes the characteristics of porous 3C-SiC with in-situ N-doping concentrations. Polycrystalline (poly) 3C-SiC thin films were deposited on p-type Si (100) substrates by APCVD using hexamethyildisilane (HMDS: Si2(CH3)6). The porous 3C-SiC (pSiC) was achieved by anodized with 380 nm UV-LED. The characteristics of the N2 doped pSiC were evaluated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and photo luminescence (PL). Average pore diameter is about 50 nm and etched area was increased with N2 doping rate. These results are attributed to decrease the crystallinity by N2 doping. The band gaps of poly 3C-SiC films and porous 3C-SiC films were 2.5 eV and 2.7 eV, respectively.

Growth and characterization of nitrogen-doped polycrystalline 3C-SiC thin films for harsh environment MEMS applications

Polycrystalline 3C-SiC films, in situ doped with nitrogen, are grown by low-pressure chemical vapor deposition (LPCVD) on 100 mm Si (1 0 0) wafers at 800 °C using methylsilane and ammonia precursors. The effects of NH3 and dichlorosilane precursor, as an additional silicon source, on material properties such resistivity, residual stress, strain, strain gradient as well as crystallinity and surface morphology are investigated. By varying these parameters, the electrical and mechanical properties of the films are optimized for MEMS applications. Films with a resistivity of 0.026 ± 0.001 Ω cm, residual stress of 254 ± 16 MPa and strain of 4.5 × 10−4, corresponding to the biaxial modulus of 564 GPa, and strain gradient of 5.8 × 10−4 µm−1 are achieved.

Analysis of mechanical properties of N 2in situ doped polycrystalline 3C-SiC thin films by chemical vapor deposition using single-precursor hexamethyildisilane

This paper describes the mechanical properties of poly (polycrystalline) 3C-SiC thin films with N 2 in situ doping. In this work, in situ doped poly 3C-SiC film was deposited by using the atmospheric pressure chemical vapor deposition (APCVD) method at 1200 °C using single-precursor hexamethyildisilane: Si 2(CH 3) 6 (HMDS) as Si and C precursors, and 0∼100 sccm N 2 as the dopant source gas. The mechanical properties of doped poly 3C-SiC thin films were measured by nano-indentation. Young's modulus and hardness were measured to be 285 and 35 GPa at 0 sccm N 2, respectively. Young's modulus and hardness decreased with increasing N 2 flow rate. Surface morphology was evaluated by atomic force microscopy (AFM) according to N 2 flow rate.

Growth and characteristics of polycrystalline 3C–SiC films for extreme environment micro/nano-electromechanical systems

This paper presents the growth conditions, physical, chemical, mechanical and optical characteristics of polycrystalline 3C–SiC films for extreme environment micro/nano-electromechanical systems (M/NEMS). The growth of the polycrystalline 3C–SiC thin film on oxidized Si wafers was carried out by using atmospheric pressure chemical vapor deposition (APCVD) with a single-precursor of hexamethyldisilane (HMDS: Si 2(CH 3) 6). The growth temperature and the HMDS flow rate were adjusted from 1000 to 1200 °C and from 6 to 8 sccm, respectively. The effect of H 2 carrier gas addition was also evaluated to reduce surface roughness and improve mechanical properties. The grown polycrystalline 3C–SiC films grown in this work had very good crystal quality without twins, defects, or dislocations. Therefore, it is expected to have applications in harsh environment, RF and bio M/NEMS devices.

Residual stress characterization of polycrystalline 3C-SiC films on Si(100) deposited from methylsilane

Polycrystalline 3C-SiC thin films are deposited on 100 mm Si(100) wafers via low pressure chemical vapor deposition from the precursor methylsilane in the temperature range of 700–850 °C. Residual stress, strain, and strain gradient are characterized as functions of deposition pressure, temperature, and dichlorosilane as an additional silicon source. By optimizing the deposition parameters, the residual stress is found to decrease from 1377±10 to 196±19 MPa. The low stress film exhibits a strain of 3.4×10−4, corresponding to Young’s modulus of 455 GPa, and strain gradient of −8×10−4 μm−1. The analysis suggests that the change in stress values is due to a combination of effects, in particular, thermal mismatch, grain size effect, and chemical composition.

Pd/다결정 3C-SiC 쇼트키 다이오드형 수소센서의 제작과 그 특성

This paper describes the fabrication and characteristics of Schottky micro hydrogen sensors for high temperatures by using polycrystalline(poly) 3C-SiC thin films grown on Si substrates with thermal oxide layer using APCVD. Pd/poly 3C-SiC Schottky diodes were made and evaluated by I-V and C-V measurements. Electric current density and barrier height voltage were and 0.58 eV, respectively. These devices could operate stably at about 400 . The characteristics of implemented sensors have been investigated in terms of sensitivity, linearity of response, response rate, and response time. Therefore, from these results, Pd/poly 3C-SiC Schottky devices have very high potential for high temperature sensor applications.

APCVD로 in-situ 도핑된 다결정 3C-SiC 박막의 기계적 특성

This paper describes the mechanical properties of poly (Polycrystalline) 3C-SiC thin films with <TEX>$N_2$</TEX> in-situ doping. In this work, the poly 3C-SiC film was deposited by APCVD (Atmospheric Pressure Chemical Vapor Deposition) method using single-precursor HMDS (Hexamethyildisilane: <TEX>$Si_2(CH_3)_6)$</TEX> at <TEX>$1200^{\circ}C$</TEX>. The mechanical properties of doped poly 3C-SiC thin films were measured by nono-indentation according to the various <TEX>$N_2$</TEX> flow rate. In the case of 0 sccm <TEX>$N_2$</TEX> flow rate, Young's Modulus and hardness were obtained as 285 GPa and 35 GPa, respectively. Young's Modulus and hardness were decreased according to increase of <TEX>$N_2$</TEX> flow rate. The crystallinity and surface roughness was also measured by XRD (X-Ray Diffraction) and AFM (Atomic Force Microscopy), respectively.

Thickness-Dependant Electrical Characteristics of Nitrogen-Doped Polycrystalline 3C-SiC Thin Films Deposited by LPCVD

AbstractThe effect of film thickness on the electrical resistivity of heavily-nitrogen-doped polycrystalline SiC (poly-SiC) thin films is investigated. The resistivity of poly-SiC thin films decreases by a factor of ˜7 for thickness increasing from 100 nm-thick to 1.78 μm-thick; the resistivity begins to stabilize as thickness approaches 1 μm. The increased resistivity for the thinner films is shown to be related to the grain boundary effect. Secondary ion mass spectrometry indicates a nitrogen concentration of 9×1020 atoms/cm3 in the films. However, Hall measurements reveal that only 45% of the dopants are electrically active in the 100 nm-thick film. The percentage of active dopants rises to 80% when film thickness increases to 680 nm. From the studies of surface roughness and microstructure, it is seen that small grains are formed at the initial stage of deposition, which then grow into larger columnar grains as film thickness increases. The presence of a large density of grain boundaries and limited grain growth for the very thin films contribute to increased electrical resistivity from increased trapped mobile carriers and reduced carrier mobility. The free carrier trapping phenomenon can further be observed in the temperature-dependence of resistance measurement.

Electrical and Mechanical Characterization of Doped and Annealed Polycrystalline 3C-SiC Thin Films

+Deposition of doped polycrystalline 3C-SiC thin films from the precursors 1,3-disilabutane (DSB) and dichlorosilane (DCS), and the dopant precursor ammonia is investigated in a large-scale low-pressure chemical vapor deposition (LPCVD) reactor for micro- and nanoelectromechanical systems (M/NEMS) applications. Films deposited from only DSB and have residual stresses in excess of tensile and resistivity values of . Addition of DCS yields films that exhibit mechanical and electrical properties more favorable for M/NEMS devices. For films deposited with DCS, electrical resistivity varies between for undoped, as-deposited films to for films doped with nitrogen. Residual stress of films deposited from DSB, DCS, and varies little for as-deposited films with different doping concentrations; however, annealing in an argon ambient shifts residual stress toward, and in some cases, into the compressive regime. The strain gradient, which is less than in magnitude for all as-deposited films from DSB, DCS, and , shifts to large negative values in excess of upon annealing for at in an argon ambient. Two sources of stress shift with annealing are identified, namely oxygen diffusion and a change in N atom bonding.

Young's Modulus and Hardness Characteristics of In-Situ-Doped Polycrystalline 3C-SiC Thin Films Measured by Using a Nanoindenter

Young's Modulus and Hardness Characteristics of In-Situ-Doped Polycrystalline 3C-SiC Thin Films Measured by Using a Nanoindenter

In-situ 도핑된 M/NEMS용 다결정 3C-SiC 박막의 특성

This paper describes the electrical properties of poly (polycrystalline) 3C-SiC thin films with different nitrogen doping concentrations. In-situ doped poly 3C-SiC thin films were deposited by APCVD at <TEX>$1200^{\circ}C$</TEX> using HMDS (hexamethyildisilane: <TEX>$Si_2(CH_3)_6)$</TEX>) as Si and C precursor, and <TEX>$0{\sim}100$</TEX> sccm <TEX>$N_2$</TEX> as the dopant source gas. The peak of SiC is appeared in poly 3C-SiC thin films grown on <TEX>$SiO_2/Si$</TEX> substrates in XRD(X-ray diffraction) and FT-IR(Fourier transform infrared spectroscopy) analyses. The resistivity of poly 3C-SiC thin films decreased from <TEX>$8.35{\Omega}{\cdot}cm$</TEX> with <TEX>$N_2$</TEX> of 0 sccm to <TEX>$0.014{\Omega}{\cdot}cm$</TEX> with 100 sccm. The carrier concentration of poly 3C-SiC films increased with doping from <TEX>$3.0819{\times}10^{17}$</TEX> to <TEX>$2.2994{\times}10^{19}cm^{-3}$</TEX> and their electronic mobilities increased from 2.433 to <TEX>$29.299cm^2/V{\cdot}S$</TEX>, respectively.

Etching Characteristics of Polycrystalline 3C-SiC Films Using Enhanced RIE

This paper describes magnetron reactive ion etching (RIE) characteristics of polycrystalline (poly) 3C-SiC thin films grown on thermally oxidized Si substrates by atmospheric pressure chemical vapor deposition (APCVD). The best vertical structures were obtained by the addition of 40 % O2, 16 % Ar, and 44 % CHF3 reactive gas at 40 mTorr of chamber pressure. Stable etching was achieved at 70 W and the poly 3C-SiC was undamaged. These results show that in a magnetron RIE system, it is possible to etch SiC with lower power than that of the commercial RIE system. Therefore, poly 3C-SiC etched by magnetron RIE has the potential to be applied to micro/nano electro mechanical systems (M/NEMS).

Characteristics of Polycrystalline 3C-SiC Thin Films Grown on AlN Buffer Layer by CVD

This paper describes the characteristics of poly (Polycrystalline) 3C-SiC grown on SiO2 and AlN buffers, respectively. The crystallinity and the bonding structure of poly 3C-SiC grown on each buffer layer were investigated according to various growth temperatures. The crystalline quality of poly 3C-SiC was improved from resulting in decrease of FWHM (Full width half maximum) of XRD and FT-IR by increasing the growth temperature. The minimum growth temperature of poly 3C-SiC was 1100 °C. The surface chemical composition and the electron mobility of poly 3C-SiC grown on each buffer layer were investigated by XPS and Hall Effect. The chemical compositions of surface of poly 3C-SiC grown on SiO2 and AlN were not different. However, their electron mobilities were 7.65 ㎝2/V.s and 14.8 ㎝2/V.s, respectively. Therefore, since the electron mobility of 3C-SiC/AlN was two times higher than that of 3C-SiC/SiO2, AlN is a suitable material, as buffer layer, for SiC growth with excellent crystalline quality.

Electrical Characteristics of In-Situ-Doped Polycrystalline 3C-SiC Thin Films Deposited by Using CVD

Electrical Characteristics of In-Situ-Doped Polycrystalline 3C-SiC Thin Films Deposited by Using CVD