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1.
We have grown In0.5Ga0.5N films on SiO2/Si (100) substrate at 100–400 °C for 90 min by rf reactive sputtering with single cermet target. The target was made by hot pressing the mixture of metallic indium, gallium and ceramic gallium nitride powder. X-ray diffraction (XRD) measurements indicated that In0.5Ga0.5N films had wurtzite structure and showed the preferential (1 0 -1 0) diffraction. Both SEM and AFM showed that In0.5Ga0.5N films were smooth and had small roughness of 0.6 nm. Optical properties were measured by photoluminescence (PL) spectra from room temperature to low temperature of 20 K. The 2.28 eV green emission was achieved at room temperature for all our InGaN films. The electrical properties of In0.5Ga0.5N films on a SiO2/Si (100) substrate were measured by the Hall measurement at room temperature. InGaN films showed the electron concentration of 1.51×1020–1.90×1020 cm−3 and mobility of 5.94–10.5 cm2 V−1 s−1. Alloying of InN and GaN was confirmed for the sputtered InGaN. 相似文献
2.
P. Dimitrakis A. Mouti C. Bonafos S. Schamm G. Ben Assayag V. Ioannou-Sougleridis B. Schmidt J. Becker P. Normand 《Microelectronic Engineering》2009,86(7-9):1838-1841
Structural and electrical properties of ALD-grown 5 and 7 nm-thick Al2O3 layers before and after implantation of Ge ions (1 keV, 0.5–1 × 1016 cm?2) and thermal annealing at temperatures in the 700–1050 °C range are reported. Transmission Electron Microscopy reveals the development of a 1 nm-thick SiO2-rich layer at the Al2O3/Si substrate interface as well as the formation of Ge nanocrystals with a mean diameter of ~5 nm inside the implanted Al2O3 layers after annealing at 800 °C for 20 min. Electrical measurements performed on metal–insulator–semiconductor capacitors using Ge-implanted and annealed Al2O3 layers reveal charge storage at low-electric fields mainly due to location of the Ge nanocrystals at a tunnelling distance from the substrate and their spatial dispersion inside the Al2O3 layers. 相似文献
3.
ZnS thin films were deposited from four different zinc salts on glass substrates by chemical bath deposition method. Different anions of zinc salts affect the deposition mechanism and growth rate, which influence the properties of the films significantly. The ZnS thin film deposited from ZnSO4 is smoother, thicker, more homogeneous and compact, nearly stoichiometric, comparing with the films deposited from Zn(CH3COO)2 and Zn(NO3)2, and ZnCl2. The scratch test of bonding force between ZnS film and substrate shows that the ZnS film deposited from ZnSO4 has the most excellent adhesion with the substrate. The presence of SO42− promotes heterogeneous ZnS thin film growth via ions by ions deposition, and the films deposited from Zn(CH3COO)2 and Zn(NO3)2 are formed via clusters by clusters deposition. XRD and HRTEM results show that cubic ZnS films are obtained after single deposition, and the grain size of ZnS thin film deposited from ZnSO4 for 2.5 h is 10 nm. The average transmission of all films is greater than 85% in the wavelength ranging from 600 to 1100 nm, and the transmission of films deposited from ZnSO4 or Zn(NO3)2 for 1.5, 2 and 2.5 h is greater than 85% in the wavelength varying from 340 to 600 nm, which can enhance the blue response. The band gaps of all ZnS thin films are in the range of 3.88–3.99 eV. After annealing treatment, the mechanical and optical properties of the ZnS thin film deposited from ZnSO4 are improved significantly. 相似文献
4.
《Organic Electronics》2008,9(5):602-608
Highly crystalline polyaniline (PANI) films were deposited on degenerated silicon (n+-Si) substrates covered with its native oxide (SiO2), surface modified with amino-silane self-assembled monolayers (SAM). Scanning electron microscopy studies reveal formation of single crystal domains scattered all over the surface of film. Height and current images obtained using current-sensing AFM (C-AFM) exhibit pyramidal topography of crystallites, and inhomogeneous conductivity. As the native oxide and SAM acts as a very thin insulating layer (<2 nm) between the metal-like substrate (degenerated Si) and the PANI film, it forms n+-Si/SiO2/SAM/PANI metal-insulator-semiconductor (MIS) heterostructure. C-AFM probe was used for I–V measurements on the MIS structures and study the tunneling conduction across it. The conductance spectra derived from I–V characteristics corroborates well with the polaron-lattice band structure of doped PANI with presence of polaron bands between the HOMO-LUMO energy gap. These polaron bands are well-resolved from our C-AFM measurements and they are located about 0.25 eV below the LUMO and above the HOMO. 相似文献
5.
W.L. Li J.M. Wang C.Q. Liu W.D. Fei 《Materials Science in Semiconductor Processing》2010,13(5-6):426-429
The lead magnesium niobate–lead titanate (PMN–PT) thin films with and without the TiO2 seed layer were prepared by a pulsed laser deposition (PLD) deposited on Pt/Ti/SiO2/Si substrates. The films were treated by two-step annealing and normal annealing with rapid thermal annealing (RTA). The effects of two-step annealing and the TiO2 seed layer on the phase composition of PMN–PT films were studied. The results show that the PMN–PT film with TiO2 seed layer can gain a pure perovskite phase with a high (1 0 0) preferential orientation after the two-step annealing technique. 相似文献
6.
The aim of this work was to develop high quality of CuIn1−xGaxSe2 thin absorbing films with x (Ga/In+Ga)<0.3 by sputtering without selenization process. CuIn0.8Ga0.2Se2 (CIGS) thin absorbing films were deposited on soda lime glass substrate by RF magnetron sputtering using single quaternary chalcogenide (CIGS) target. The effect of substrate temperature, sputtering power & working pressure on structural, morphological, optical and electrical properties of deposited films were studied. CIGS thin films were characterised by X-ray diffraction (XRD), Field emission scanning electron microscope (FE-SEM), Energy dispersive X-ray spectroscopy (EDAX), Atomic force microscopy (AFM), UV–vis–NIR spectroscopy and four probe methods. It was observed that microstructure, surface morphology, elemental composition, transmittance as well as conductivity of thin films were strongly dependent on deposition parameters. The optimum parameters for CIGS thin films were obtained at a power 100 W, pressure 5 mT and substrate temperature 500 °C. XRD revealed that thin film deposited at above said parameters was polycrystalline in nature with larger crystallite size (32 nm) and low dislocation density (0.97×1015 lines m−2). The deposited film also showed preferred orientation along (112) plane. The morphology of the film depicted by FE-SEM was compact and uniform without any micro cracks and pits. The deposited film exhibited good stoichiometry (Ga/In+Ga=0.19 and In/In+Ga=0.8) with desired Cu/In+Ga ratio (0.92), which is essential for high efficiency solar cells. Transmittance of deposited film was found to be very low (1.09%). The absorption coefficient of film was ~105 cm−1 for high energy photon. The band gap of CIGS thin film evaluated from transmission data was found to be 1.13 eV which is optimum for solar cell application. The electrical conductivity (7.87 Ω−1 cm−1) of deposited CIGS thin film at optimum parameters was also high enough for practical purpose. 相似文献
7.
G. Congedo S. Spiga L. Lamagna A. Lamperti Yu. Lebedinskii Yu. Matveyev A. Zenkevich P. Chernykh M. Fanciulli 《Microelectronic Engineering》2009,86(7-9):1696-1699
Amorphous lanthanum aluminate thin films were deposited by atomic layer deposition on Si(1 0 0) using La(iPrCp)3, Al(CH3)3 and O3 species. The effects of post-deposition rapid thermal annealing on the physical and electrical properties of the films were investigated. High-temperature annealing at 900 °C in N2 atmosphere leads to the formation of amorphous La-aluminosilicate due to Si diffusion from the substrate. The annealed oxide exhibits a uniform composition through the film thickness, a large band gap of 7.0 ± 0.1 eV, and relatively high dielectric constant (κ) of 18 ± 1. 相似文献
8.
Sang-Jin Jeon Jong-Woong Chang Kwang-Soo Choi Jyoti Prakash Kar Tae-Il Lee Jae-Min Myoung 《Materials Science in Semiconductor Processing》2010,13(5-6):320-324
We have studied the characteristics of transparent bottom-gate thin film transistors (TFTs) using In–Ga–Zn–O (IGZO) as an active channel material. IGZO films were deposited on SiO2/Si substrates by DC sputtering techniques. Thereafter, the bottom-gate TFT devices were fabricated by depositing Ti/Au metal pads on IGZO films, where the channel length and width were defined to be 200 and 1000 μm, respectively. Post-metallization thermal annealing of the devices was carried out at 260, 280 and 300 °C in nitrogen ambient for 1 h. The devices annealed at 280 °C have shown better characteristics with enhanced field-effect mobility and high on–off current ratio. The compositional variation of IGZO films was also observed with different annealing temperatures. 相似文献
9.
T. Indira Gandhi R. Ramesh Babu K. Ramamurthi 《Materials Science in Semiconductor Processing》2013,16(2):472-479
Tin oxide (SnO2) and chromium (Cr) doped tin oxide (Cr:SnO2) thin films were deposited on the preheated glass substrates at 673 K by spray pyrolysis. Concentration of Cr was varied in the solution by adding chromium (III) chloride hexahydrate from 0 to 3 at%. The effect of Cr doping on the structural, electrical and optical properties of tin oxide films is reported. X-ray diffraction pattern confirms the tetragonal crystal structure for undoped and Cr doped tin oxide films. Scanning electron microscopic photographs show the modification of surface morphology of tin oxide film due to varying concentration of Cr. X-ray photoelectron spectra of Cr:SnO2 (3 at%) thin film revealed the presence of carbon, tin, oxygen, and chromium. Carrier concentration and mobility of the SnO2 films decrease with increasing concentration of Cr and 0.5 at% Cr doped tin oxide film acquires a mobility of 70 cm2/V s. Average optical transmittance in the 550–850 nm range varies from 38% to 47% with varying Cr concentration in the solution. 相似文献
10.
S. Prasanna G. Krishnendu S. Shalini P. Biji G. Mohan Rao S. Jayakumar R. Balasundaraprabhu 《Materials Science in Semiconductor Processing》2013,16(3):705-711
Thin films of alumina (Al2O3) were deposited over Si 〈1 0 0〉 substrates at room temperature at an oxygen gas pressure of 0.03 Pa and sputtering power of 60 W using DC reactive magnetron sputtering. The composition of the as-deposited film was analyzed by X-ray photoelectron spectroscopy and the O/Al atomic ratio was found to be 1.72. The films were then annealed in vacuum to 350, 550 and 750 °C and X-ray diffraction results revealed that both as-deposited and post deposition annealed films were amorphous. The surface morphology and topography of the films was studied using scanning electron microscopy and atomic force microscopy, respectively. A progressive decrease in the root mean square (RMS) roughness of the films from 1.53 nm to 0.7 nm was observed with increase in the annealing temperature. Al–Al2O3–Al thin film capacitors were then fabricated on p-type Si 〈1 0 0〉 substrate to study the effect of temperature and frequency on the dielectric property of the films and the results are discussed. 相似文献
11.
《Materials Science in Semiconductor Processing》2002,5(2-3):233-236
The high-k dielectric material (Ba,Sr)TiO3 has been intensively investigated for possible applications in dynamic random access memory circuits. During the BST deposition process in O2 ambient, typically at 650°C, the diffusion of oxygen through the bottom electrode into the poly Si plug must be prevented. Amorphous TaSiN films are excellent candidates as oxygen barrier layers. Ba0.5Sr0.5TiO3 (BST) films with thickness of 100 nm were deposited on the electrode structure SiO2/TaSiN/Pt. The sol–gel method was used to grow the BST films. The barrier effect for oxygen diffusion is studied in TaSiN layers with thickness of 50 nm, which were deposited by a reactive sputter process. X-ray photoemission spectroscopy results confirm that this amorphous material is a suitable barrier against oxygen diffusion at 650°C. The BST films, deposited at 650°C and post-annealed at 650°C show a dielectric constant of 100 at 100 kHz and a dissipation factor of less than 5%. 相似文献
12.
《Materials Science in Semiconductor Processing》2012,15(4):432-437
Tin oxide (SnO2) thin films were deposited on glass substrates by thermal evaporation at different substrate temperatures. Increasing substrate temperature (Ts) from 250 to 450 °C reduced resistivity of SnO2 thin films from 18×10−4 to 4×10−4▒ Ω ▒cm. Further increase of temperature up to 550 °C had no effect on the resistivity. For films prepared at 450 °C, high transparency (91.5%) over the visible wavelength region of spectrum was obtained. Refractive index and porosity of the layers were also calculated. A direct band gap at different substrate temperatures is in the range of 3.55−3.77 eV. X-ray diffraction (XRD) results suggested that all films were amorphous in structure at lower substrate temperatures, while crystalline SnO2 films were obtained at higher temperatures. Scanning electron microscopy images showed that the grain size and crystallinity of films depend on the substrate temperature. SnO2 films prepared at 550 °C have a very smooth surface with an RMS roughness of 0.38 nm. 相似文献
13.
Recently, nanostructured thin films have attracted the attention of researchers from several disciplines, due to their outstanding electronic and optical properties and potential applications in various optoelectronic devices. The ternary Cd0.5Fe0.5Se nanocrystalline thin films were deposited by a spray pyrolysis method onto glass, aluminium, copper and stainless steel substrates. The structural and morphological properties were studied by X-ray diffraction and scanning electron microscopy analysis. The XRD study revealed that, Cd0.5Fe0.5Se films are nanocrystalline in nature with hexagonal lattice. The optical absorption study showed that, the semiconductor Cd0.5Fe0.5Se thin film deposited on glass exhibits direct band gap energy of the order of 1.95 eV. The PEC study revealed that, Cd0.5Fe0.5Se thin films deposited on aluminium substrate exhibited maximum fill factor (FF) and efficiency (η) as compared to the films deposited on stainless steel and copper substrates. 相似文献
14.
Highly oriented crystalline aluminum doped zinc oxide (AZO) films were sputter deposited on glass substrates and a systematic investigation on the as deposited and etched films was reported for its further application in silicon thin film solar cell. Influence of the deposition pressure (from 2 to 8 mTorr) and post-annealing temperature (at 400 °C for 5 min) on the structural, optical and electrical properties of the as-deposited and etched samples were analyzed. The optimum condition for its reproducibility and large area deposition is determined and found that the depositions made at 8 mTorr at 200 W having the distance from source to substrate of 9 cm. All the AZO films exhibited a c-axis preferred orientation perpendicular to the substrate and their crystallinity was improved after annealing. From the XRD pattern the grain size, stress and strain of the films were evaluated and there is no drastic variation. Optical transmittance, resistivity, Hall mobility and carrier concentration for the as deposited and etched-annealed films were found to improve from 79 to 82%; 2.97 to 3.14×10−4 Ω cm; 25 to 38 cm2/V s; 8.39 to 5.96×1020/cm3 respectively. Based on the triangle diagram between figure of merit and Hall mobility, we obtained a balance of point between the electrical and optical properties to select the deposition condition of film for device application. 相似文献
15.
In this work, the B-doped Si rich oxide (SRO) thin films were deposited and then annealed using rapid thermal annealing (RTA) to form SiO2-matrix silicon nanocrystals (Si NCs). The effects of the RTA temperatures on the structural properties, conduction mechanisms and electrical properties of B-doped SRO thin films (BSF) were investigated systematically using Hall measurements, Fourier transform infrared spectroscopy and Raman spectroscopy. Results showed that the crystalline fraction of annealed BSF increased from 41.3% to 62.8%, the conductivity was increased from 4.48×10−3 S/cm to 0.16 s/cm, the carrier concentration was increased from 8.74×1017 cm−3 to 4.9×1018 cm−3 and the carrier mobility was increased from 0.032 cm2 V−1 s−1 to 0.2 cm2 V−1 s−1 when the RTA temperatures increased from 1050 °C to 1150 °C. In addition, the fluctuation induced tunneling (FIT) theory was applicable to the conduction mechanisms of SiO2-matrix boron-doped Si-NC thin films. 相似文献
16.
R. Roucka Y.-J. An A.V.G. Chizmeshya V.R. D’Costa J. Tolle J. Menéndez J. Kouvetakis 《Solid-state electronics》2008,52(11):1687-1690
ZrB2 and HfxZr1?xB2 films were grown on 4° miscut Si(1 1 1) substrates by chemical vapor deposition of gaseous Hf(BH4)4 and Zr(BH4)4. The films display superior structural and optical properties when compared with ZrB2 films grown on on-axis Si(1 1 1). The observed improvements include an optically featureless surface with rms roughness of ~2.5–3.5 nm, a ~50% reduction in the amount of residual strain, and a ~50% lower resistivity. These properties should promote the use of diboride films as buffer layers for nitride semiconductor epitaxy on large-area Si substrates. 相似文献
17.
Samerkhae Jongthammanurak Maetapa Witana Tinnaphob Cheawkul Chanchana Thanachayanont 《Materials Science in Semiconductor Processing》2013,16(3):625-632
ZnO films were deposited on glass substrates in the temperature range of 350–470 °C under an atmosphere of compressed air or nitrogen (N2) by using ultrasonic spray pyrolysis technique. Structural, electrical and optical properties of the ZnO films were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), electrical two-probe and optical transmittance measurements. The ZnO films deposited in the range of 350–430 °C were polycrystalline with the wurtzite hexagonal structure having preferred orientation depending on the substrate temperature. The ZnO films deposited below 400 °C had a preferred (100) orientation while those deposited above 400 °C mostly had a preferred (002) orientation. The resistivity values of ZnO films depended on the types of carrier gas. The ZnO thin films deposited under N2 atmosphere in the range of 370–410 °C showed dense surface morphologies and resistivity values of 0.6–1.1 Ω-cm, a few orders of magnitude lower than those deposited under compressed air. Hydrogen substition in ZnO possibly contributed to decreasing resistivity in ZnO thin films deposited under N2 gas. The Hall measurements showed that the behavior of ZnO films deposited at 410 °C under the N2 atmosphere was n-type with a carrier density of 8.9–9.2×1016 cm-3 and mobility of ~70 cm2/Vs. ZnO thin films showed transmission values at 550 nm wavelength in a range of 70–80%. The values of band gaps extrapolated from the transmission results showed bandgap shrinkage in an order of milli electron volts in ZnO films deposited under N2 compared to those deposited under compressed air. The calculation showed that the bandgap reduction was possibly a result of carrier–carrier interactions. 相似文献
18.
By using our low-energy Ar plasma enhanced chemical vapor deposition (CVD) at a substrate temperature below 100 °C during plasma exposure without substrate heating, modulation of valence band structures and infrared photoluminescence can be observed by change of strain in a Si/strained Si0.4Ge0.6/Si(100) heterostructure. For the strained Si0.5Ge0.5 film, Hall mobility at room temperature was confirmed to be as high as 660 cm2 V−1 s−1 with a carrier concentration of 1.3×1018 cm−3 for n-type carrier, although the carrier origin was unclear. Moreover, good rectifying characteristics were obtained for a p+Si/nSi0.5Ge0.5 heterojunction diode. This indicates that the strained Si-Ge alloy and Si films and their heterostructures epitaxially grown by our low-energy Ar plasma enhanced CVD without substrate heating can be applicable effectively for various semiconductor devices utilizing high carrier mobility, built-in potential by doping and band engineering. 相似文献
19.
Manganese indium sulphide (MnIn2S4) thin films were deposited using an aqueous solution of MnCl2, InCl3 and (NH2)2CS in the molar ratio 1:2:4 by simple chemical spray pyrolysis technique. The thin film substrates were annealed in the temperature range between 250 and 350 °C to study their various physical properties. The structural properties as studied by X-ray diffraction showed that MnIn2S4 thin films have cubic spinel structure. The formation of cube and needle shaped grains was clearly observed from FE-SEM analysis. The energy dispersive spectrum (EDS) predicts the presence of Mn, In and S in the synthesized thin film. From the optical studies, it is analyzed that the maximum absorption co-efficient is in the order between 104 and 105 cm−1 and the maximum transmittance (75%) was noted in the visible and infrared regions. It is noted that, the band gap energy decreases (from 3.20 to 2.77 eV) with an increase of substrate temperature (from 250 to 350 °C). The observations from photoluminescence studies confirm the emission of blue, green, yellow and red bands which corresponds to the wavelength range 370–680 nm. Moreover, from the electrical studies, it is observed that, as the substrate temperature increases the conductivity also increases in the range 0.29–0.41×10−4 Ω−1 m−1. This confirms the highly semiconducting nature of the film. The thickness of the films was also measured and the values ranged between 537 nm (250 °C) to 483 nm (350 °C). This indicates that, as the substrate temperature increases, the thickness of the film decreases. From the present study, it is reported that the MnIn2S4 thin films are polycrystalline in nature and can be used as a suitable ternary semiconductor material for photovoltaic applications. 相似文献
20.
《Materials Science in Semiconductor Processing》2012,15(3):293-300
Aluminum oxide-doped zinc oxide (ZnO:Al2O3) transparent thin films were deposited by DC magnetron sputtering on glass substrates; film thickness can be correlated with deposition time. The effect of ZnO:Al2O3 film thickness on electrical properties, ultraviolet (UV) transmission, surface morphology and structure, solvent resistance, and scratch hardness was investigated. The surface roughness and crystallite size of deposited films increased from 0.75 to 2.22 nm and from 14 to 57 nm, respectively, as the film thickness was increased from 18 to 112 nm. In contrast, the percent UV transmission (% T) of ZnO:Al2O3 deposited glass plates at a wavelength of 365 nm increased when the film thickness was decreased. The electrical properties of nano-film deposited glass plates such as electrical resistance, tribo-charge voltage, and decay time were in the range of electrostatic discharge (ESD) specifications. The ZnO:Al2O3 nano-film deposited glass substrate possessed good acetone and iso-propanol resistance as well as high scratch hardness. This work opens up the possibility of using the ZnO:Al2O3 transparent ultra-thin film on glass substrate in ESD applications based on their excellent properties in terms of the relatively thin and adjustable ZnO:Al2O3 film thickness needed. 相似文献