Evolution of microstructural and electrical properties of sputtered HfO2 ceramic thin films with RF power and substrate temperature

Das, Kailash Chandra; Ghosh, Subhojit; Tripathy, N.; Kim, D.H.; Lee, T.I.; Myoung, Jae Min; Kar, Jyoti Prakash

doi:10.1016/j.ceramint.2015.08.038

Cited by 19 publications

(11 citation statements)

References 27 publications

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“…In contrast, Das et al [73] showed that the RMS roughness of hafnium oxide (HfO 2 ) films decreased from about 1.52 to 0.65 nm as the deposition power increased from 75 to 300 W, as shown in figure 4 and table 3. This was explained by the nucleation and growth of crystallites at different deposition powers [73]. The increasing deposition power increased the mobility of the impinging atoms on the surface before they condensed and were trapped in the film [62].…”

Section: Effects Of Different Deposition Powers On the Surface Roughn...mentioning

confidence: 91%

“…References [66,[70][71][72][73][74][75] reported the surface roughness of metal and compound films gown via RF magnetron sputtering at different RF powers. Table 3 lists the test results and the deposition conditions in detail.…”

Section: Effects Of Different Deposition Powers On the Surface Roughn...mentioning

confidence: 99%

“…This section mainly discusses the effects of substrate temperature on the surface roughness of the grown films via RF and DC magnetron sputtering. Some researchers have analyzed the surface roughness of compound films deposited by RF magnetron sputtering at different substrate temperatures [58,73,86,114]. Freixas et al [58] and Das et al [73] reported that the surface roughness of the deposited films decreased with the substrate temperature.…”

Section: Effects Of Different Substrate Temperatures On the Surface R...mentioning

confidence: 99%

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Effect of deposition parameters on surface roughness and consequent electromagnetic performance of capacitive RF MEMS switches: a review

Chen

Tian

Zhang

et al. 2017

J. Micromech. Microeng.

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Surface roughness seriously affects the electromagnetic performance of capacitive radio frequency (RF) micro-electromechanical system (MEMS) switches. This review presents the effects of different film thickness values, substrate topologies, sputtering powers, gas pressures, gas ratios, substrate temperatures and annealing temperatures on the surface roughness of deposited thin films. At the same time, the mechanisms of the deposition parameters on the surface roughness are also analyzed. The effects of surface roughness on the electromagnetic performance of capacitive RF MEMS switches are then discussed in detail. Finally, two different methods for improving the surface roughness of deposited thin films are given.

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Section: Effects Of Different Deposition Powers On the Surface Roughn...mentioning

confidence: 91%

Section: Effects Of Different Deposition Powers On the Surface Roughn...mentioning

confidence: 99%

Section: Effects Of Different Substrate Temperatures On the Surface R...mentioning

confidence: 99%

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Effect of deposition parameters on surface roughness and consequent electromagnetic performance of capacitive RF MEMS switches: a review

Chen

Tian

Zhang

et al. 2017

J. Micromech. Microeng.

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“…Nanostructured metal oxide semiconductors with wide band gaps have been synthesized and studied by many researchers during recent decades because of their applications in solar cells, photocatalysis and gas sensors. Hafnium oxide is a transition metal oxide with a band gap energy of more than 5.0 eV and dielectric constant of more than 25 [1]. Because of its high mechanical and thermal stability, HfO 2 is widely used for protective coatings and waveguides [2,3].…”

Section: Introductionmentioning

confidence: 99%

Enhanced room temperature sensitivity of undoped HfO2 nanoparticles towards formaldehyde gas

Chattopadhyay

Nayak

2021

Appl. Phys. A

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Hafnium oxide (HfO 2 ) nanoparticulate powders were synthesized via a single step sol gel route using citric acid and ethylene glycol as chelating agent and polymerizing agent, respectively. In order to burn off the volatile components and produce crystalline HfO 2 nanoparticles, the powders were calcined at moderately high temperatures ranging from 500 to 800 °C for 1 h each. The crystal structures of the nanoparticles were ascertained by powder X-ray diffraction. The nanocrystals in powder form had monoclinic structure and preferred orientation of the nanocrystals along (−111) direction was evident. The morphologies of the HfO 2 nanopowders were studied by Field Emission Scanning Electron Microscope (FESEM). Morphologies of the nanopowder were observed to change with calcination temperatures. The optical properties of the HfO 2 nanoparticles were evaluated by UV-Vis Diffuse Reflectance Spectroscopy (DRS). A small change in the band gap energy of HfO 2 nanoparticles was observed with a change in the calcination temperature. In order to study the electrical and gas sensing properties of HfO 2 nanoparticles, the powders were pressed into pellets with 12.0 mm diameter and 1.5 mm thickness. Gas sensing properties of HfO 2 pellets were investigated by exposing them to formaldehyde gas inside closed chambers. The sensitivity of HfO 2 towards formaldehyde gas initially increased with an increase in the calcination temperature due to increased porosity and decreased resistance of the HfO 2 pellet. The HfO 2 powder calcined at 700 °C showed highest sensitivity of 91.2% towards 264 ppm formaldehyde gas. The sensitivity declined with further increase in the calcination temperature because the HfO 2 pellet became less porous thereby. Selectivity of the HfO 2 sensor was tested with three volatile organic compound gases: acetone, ethanol and formaldehyde. Highest response was recorded for the formaldehyde gas.

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“…Sputtering is considered as one of the most promising deposition technique for thin film deposition [20]. There are very few reports of deposition of CCTO thin film by RF sputtering [12,21].…”

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confidence: 99%

Effect of RF sputtering power on morphological and electrical properties of calcium copper titanate thin films

Tripathy

Das

Ghosh

et al. 2017

J Mater Sci: Mater Electron

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dielectric constant, but these are limited to low temperature applications. Beyond the Curie temperature (T c ) their dielectric properties decreases dramatically, which is undesirable for device applications. Recently, CaCu 3 Ti 4 O 12 (CCTO), possessing a distorted cubic perovskite structure, has received intensive consideration due to its extraordinary dielectric behavior [7]. The dielectric constant of CCTO ceramics is in the order of 10 5 over a broad range of temperature due to its stable cubic structure [8] and also no lattice distortion has been observed in CCTO between this temperature range as confirmed by neutron diffraction and high resolution X-ray diffraction [7,8]. The origin of high permittivity in CCTO is still under debate. High dielectric behavior is the common feature in ferroelectric materials. In case of CCTO, the contribution from dipoles has been ruled out due to its centrosymmetry nature even at low temperature [7,8]. The internal barrier layer mechanism is widely accepted for explanation of giant dielectric permittivity in CCTO, where the conducting grains are separated by insulating grain boundaries [9]. Application of CCTO in microelectronics for memory devices, sensors, capacitor and varistors demands the deposition of CCTO thin films on silicon substrate.Due to the unique dielectric behavior of CCTO bulk ceramics, many research groups have initiated deposition of CCTO thin films by different deposition techniques [10-16] on various types of substrates [17][18][19]. Sputtering is considered as one of the most promising deposition technique for thin film deposition [20]. There are very few reports of deposition of CCTO thin film by RF sputtering [12,21]. Sputtering parameters like RF power, deposition pressure, substrate temperature strongly influence the structural, morphological and electrical properties of thin films. In our previous work [22], we have deposited CCTO thin film with the variation of deposition pressure on silicon Abstract Calcium copper titanate (CCTO) thin films were deposited on p-type silicon substrate by RF magnetron sputtering at various RF powers. Post deposition annealing was carried out for all the samples at 950 °C for 1 h in air atmosphere. Various types of surface morphology have been observed for CCTO thin films with the variation of RF power. The evolution of polycrystalline structure of the CCTO thin films was confirmed by XRD studies. The FTIR characteristic absorption band of CCTO was observed in the range of 400-700 cm −1 . The capacitancevoltage (C-V) and current-voltage (I-V) characteristics of the films were investigated employing Al/CCTO/Si MOS capacitors. CCTO films with higher dielectric constant, lower oxide and interface charge density were obtained at higher RF power. Leakage current was also found to be minimum for RF power of 105 W.

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Evolution of microstructural and electrical properties of sputtered HfO2 ceramic thin films with RF power and substrate temperature

Cited by 19 publications

References 27 publications

Effect of deposition parameters on surface roughness and consequent electromagnetic performance of capacitive RF MEMS switches: a review

Effect of deposition parameters on surface roughness and consequent electromagnetic performance of capacitive RF MEMS switches: a review

Enhanced room temperature sensitivity of undoped HfO2 nanoparticles towards formaldehyde gas

Effect of RF sputtering power on morphological and electrical properties of calcium copper titanate thin films

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