Influence of RF power on the stoichiometry, optical, and electrical properties of chromium oxide coatings prepared by reactive magnetron sputtering

Abstract

An investigation has been carried out on the stoichiometry, optical and electrical properties of chromium oxide thin films prepared under various deposition powers using RF magnetron sputtering technique. The elemental and chemical composition of the prepared films were characterised by energy dispersive X-ray (EDX) analysis, Raman spectroscopy and Fourier transform infrared spectroscopy (FTIR). The wettability and surface energies of the thin films were investigated with a goniometer. The four-point electrical probe method was used to determine the electrical resistivity of the films while the optical properties of the films were measured with a spectrophotometer. The coatings were found to be mainly 2 3 phase based on the dominance of A1g and Eg symmetric modes in the Raman investigations and the Eu vibration mode in the FTIR measurements. The RF powers used during the deposition process were found to have played a vital role in the formation of Cr 2 O 3 rich films. It was observed that higher deposition power facilitated both the dislodging of more chromium atoms from the target and dissociation of oxygen used during the deposition process. The wettability results show that the thin films are hydrophilic and interact well with water and this behaviour is linked to the contribution of the polar component to the total surface energy. Optical transmittance values exceeding 70% were obtained for the films prepared at a lower RF power. The resistivity values varied from 0.061 Ω cm to 0.152 Ω cm for the deposited chromium oxide films. The variation in the electrical resistivity and the optical transmittance of the films with RF power indicate that these film properties can be altered or tuned to suit specific applications e.g. as transparent conducting oxide (TCO) for optoelectronic devices and other similar applications.

Production of spin coated chromium oxide (CrO3) thin layers and application in the Al/p-Si metal semiconductor structures

“…In recent years, it has been successfully realized that these materials can be synthesized in nano size and used in device production. Among the above-mentioned metal oxides, the chromium trioxide (CrO 3 ) compound has a wide range of operations due to its huge electronic conduction and optical transmittance features [6]. With a described hardness quantity of 29.8 GPa, chromium oxide can be divided into different stoichiometries, such as Cr 2 O 3 , CrO, CrO 2 , CrO 3 , Cr 3 O 4 .…”

“…With a described hardness quantity of 29.8 GPa, chromium oxide can be divided into different stoichiometries, such as Cr 2 O 3 , CrO, CrO 2 , CrO 3 , Cr 3 O 4 . As a result of stoichiometric changes caused by the preparation procedures and growth parameters utilized during the film fabrication, chromium oxide exhibits different optical and resistive properties [6][7][8]. To produce these films, physical vapor deposition (sputtering), chemical vapor deposition (CVD), metal organic chemical vapor deposition (MOCVD), sol-gel methods (dip coating, spin coating, spray coating) are used.…”

“…Assuming that there is no substantial optical band energy diversity between the crystalline and amorphous form, Hong et al [10] have discovered that the band energy decays with a rise in formation temperature from 4.7 eV to 5.0 eV for chromium oxide layers generated by DC reactive sputtering technique. The resistivity characteristics of thin films are influenced by many deposition parameters, including process temperatures, oxygen flow rate, and chamber pressure utilized during precipitation [6,11,12]. The chemical spray pyrolysis approach is used for the first time to create the thin solid layers of Cr 2 O 3 and CrO 3 .…”

“…A novel CrO 3 material, which is among these materials as an interfacial layer, is also used as an absorbing material in optical applications or in photolithography masks [6][7][8][9][10][11][12][13]. The literature does not contain systematic studies on the optical properties, structural properties, and electronic contact features of CrO 3 material.…”