ISSN (e): 2250 – 3005 || Volume, 09 || Issue, 4 || April – 2019 || International Journal of Computational Engineering Research (IJCER) www.ijceronline.com Open Access Journal Page 54 Effect of film thickness on the properties of ultrathin tantalum nitride films T. Srikanth 1,2 , R. Subba Reddy 1 , T. Vasudha 1 , K. Umamaheswari 1 , E. Yanadaiah 1 , P. Siva 1 , A. Sivasankar Reddy 1 *, V. Raja 2 , P. Sreedhara Reddy 3 1 Department of Physics, Vikrama Simhapuri University Postgraduate Centre, Kavali -524 201, A.P., India 2 NBKR Science & Arts College, Vidyanagar-524 411, Andhra Pradesh, India 3 Department of Physics, Sri Venkateswara University, Tirupati- 517 502, Andhra Pradesh, India *Corresponding Author : A. Sivasankar Reddy --------------------------------------------------------------------------------------------------------------------------------------- Date of Submission: 25-04-2019 Date of acceptance:05-05-2019 --------------------------------------------------------------------------------------------------------------------------------------- I. INTRODUCTION Tantalum nitride (TaN x ) is a promising material for many applications like microelectronic devices, diffusion barrier, optical coatings and thin film resistor due to their excellent properties such as high chemical and thermal stability, high wear resistance, and histocompatibility [1-5]. The properties of TaN x thin films are extremely sensitive to the films microstructure and morphology, andare strongly depends on the deposition technique and deposition parameters[6]. TaN x films were prepared by different thin films techniques like sputtering [7-9], cathodic arc deposition [10] and atomic layer deposition [11]. Among these techniques, sputtering is one of best techniques to prepare stoichiometry films with uniform thickness and good adhesion to substrates. In the present work, ultrathin TaN x films were deposited on glass substrates with different thickness by dc magnetron sputtering technique and investigated their structural, compositional, microstructural, surface morphology, optical and electrical properties. II. EXPERIMENTAL Ultrathin TaN x films were deposited on well cleaned glass substrates using dc magnetron sputtering. Prior to the deposition, the process chamber was evacuated until the base pressure reached under 7.8×10 -4 Pa. The target was metallic tantalum(Ta) with purity of 99.99%. The pure nitrogen and argon were used as reactive and sputtering gases, respectively.The flow rate of argon and nitrogen were controlled by mass flow controllers. Before deposition of each film the Ta target was pre-sputtered in pure argon atmosphere for 20min in order to remove oxide layers formed if any on the target. A shutter was incorporated below the sputtering target to isolate the substrate during the pre-sputtering process. This is essential in the reactive sputtering to obtain the stoichiometry films with reproducible properties. Ultrathin TaN x films were deposited on glass substrate with different thickness(5, 15 and 30nm) by varying the deposition time and keeping the other deposition parameters such as nitrogen partial pressures (4x10 -2 Pa), substrate temperature(303K), sputtering power(100W) and sputtering pressure (2Pa) as constant. During the films deposition, the substrate holder was rotated at 15rpm to obtain homogeneous film thickness. The structural properties were characterized using X-ray diffraction (XRD). X-ray photoelectron spectroscopy (XPS) was used to determine the chemical states of the films. The microstructures and surface morphology were analyzed by field emission scanning electron microscope (FE-SEM) and atomic force microscope (AFM), respectively. The transmittance of the films was recorded by UV-Vis-NIR spectrometer. The films thickness was measured by Ellipsometer measurements. Target to substrate distance was about 80mm. ABSTRACT: Ultrathin tantalum nitride (TaN x ) filmswere deposited on glass substrates by dc reactive magnetron sputtering at different thicknesses andanalyzed the structure,compositional, microstructure, surface morphology, optical and electrical properties. X-ray diffraction results showed that the deposited films have amorphous structure. The surface morphologies of the films were significantly affected by the films thickness. The RMS roughness of the films increased from 0.5 to 1.3nm by increasing the filmsthickness.The transmittance of the films decreased with increasing the films thickness. KEYWORDS: Tantalum Nitride; Ultrathin films; Sputtering; Film thickness