Growth of Thin AlN Films on Si Wafers by Reactive Magnetron Sputtering: Role of Processing Pressure, Magnetron Power and Nitrogen/Argon Gas Flow Ratio

Abstract

AlN is a wide band gap semiconductor that is of growing industrial interest due to its piezoelectric properties, high breakdown voltage and thermal conductivity. Using magnetron sputtering to grow AlN thin films allows for high deposition rates and uniform coverage of large substrates. One can also produce films at low substrate temperatures, which is required for many production processes. However, current models are inadequate in predicting the resulting structure of a thin film when different sputter parameters are varied. In this work, the growth of wurtzite AlN thin films has been carried out on Si(111) substrates using reactive direct current magnetron sputtering. The influence of the processing pressure, magnetron power and N2/Ar ratio on the structure of the grown films has been analyzed by investigating crystallinity, residual film stress and surface morphology using X-ray diffraction, profilometry, atomic force microscopy and scanning electron microscopy. In every case, the films were found to exhibit c-axis orientation and tensile stress. It was found that high-quality AlN films can be achieved at an N2/Ar ratio of 50% and a low pressure of 0.2 Pa. High magnetron powers (900–1200 W) were necessary for achieving high deposition rates, but they led to larger film stress.

Magnetron Sputter Grown AlN Nanostructures with Giant Piezoelectric Response toward Energy Generation

“…It allows for low-temperature and high-rate growth of well-oriented films on different types of substrates; it provides a high reproducibility and can be scaled up to the level of mass production. 17 Since sputter-deposited AlN films typically have columnar morphologies, 19,20 utilization of glancing angle deposition (GLAD) brings an opportunity to separate the columns, i.e., to convert them into nanorods or similar nanostructures. GLAD is already a well-developed approach which can be used in line with different physical vapor deposition methods including magnetron sputtering.…”

“…Since sputter-deposited AlN films typically have columnar morphologies, , utilization of glancing angle deposition (GLAD) brings an opportunity to separate the columns, i.e., to convert them into nanorods or similar nanostructures. GLAD is already a well-developed approach which can be used in line with different physical vapor deposition methods including magnetron sputtering. − At the nucleation stage, the material forms three-dimensional islands on the surface and the following growth occurs at a preferential orientation because the regions behind the nucleated islands are shadowed from the flux of atoms incoming at an oblique direction with respect to the surface.…”

Effects of Different Nitrogen Flow Rates on Structure and Optical Characteristics in AlN Films by Reactive Magnetron Sputtering

“…MBE and MOCVD technologies are renowned for their ability to produce lms of exceptional quality, Their cost and deposition rates limitations impede their widespread industrial adoption [10]. On the other hand, magnetron sputtering offers several advantages, including uniform lm deposition, ease of operation, and precise control, positioning it as a well-established and preferred method for large-scale production of high-quality AlN thin lms [11].…”

Magnetron Sputter Deposition of Nanostructured AlN Thin Films

“…A systematic review of reactive magnetron sputtering of AlN thin films was recently given by Mwema et al [17]. This topic has been extensively studied over several decades, yielding a large number of publications discussing different deposition strategies for tuning the film parameters in order to reach the desired properties [18][19][20][21][22][23][24][25], including PZ properties [26][27][28]. The use of glancing angle deposition (GLAD) introduces the possibility of growing films consisting of nanorods and tuning the angle they make with the surface normal [29,30].…”