Search

Fabrication of single-crystal silicon carbide thin films without any impurities is necessary for microelectromechanical systems applications. Pulsed laser deposition (PLD) of silicon carbide thin films combined with annealing can be used to grow 6H-SiC thin films in a vacuum chamber and at lower temperatures than conventional vapor deposition techniques. In the present study, the pulsed laser deposition of 6H-SiC thin films using two different silicon carbide targets and with varying substrate temperatures was investigated. In the PLD process, SiC targets prepared by two different techniques, namely, the reaction bonding technique (Carborundum Universal Limited, India) and the spark plasma sintering (SPS) technique using SiC powder (≈10.2 µm), were used. The thin films were deposited using a Nd3+:YAG (λ = 355 nm, 4 ns) laser source on silicon (1 0 0) substrates in an argon atmosphere. The post-deposited films were annealed at 1000 °C for 30 min to realize 6H-SiC. Deposition at lower temperatures between 800 and 900 °C resulted in a smooth and continuous SiC film growth with an average roughness of 2 nm. The films deposited above 950 °C formed an island pattern on the substrate. The intrinsic films were doped with nitrogen using the laser-assisted doping technique in aqueous ammonia. Electrical resistance in the films deposited with the RB-SiC target was found to be lesser than that deposited with the SPS-SiC target. [ABSTRACT FROM AUTHOR]

We have developed an Ultra-High Vacuum (UHV) compatible Pulsed Laser Deposition (PLD) set-up at Angle Resolved Photo Electron Spectroscopy (ARPES) beamline (BL-3) at Indus-1 synchrotron radiation source, Raja Ramanna Centre for Advanced Technology, Indore, India. The set-up is successfully tested and integrated at beamline for in-situ photoelectron spectroscopic (PES) studies of thin films. In present PLD set-up, quick in-situ transfer of deposited thin films to analysis chamber enables the surface sensitive PES measurements on atomically cleaned surfaces without the requirement of any sputtering. This set-up has the capability of thin film depositions using six number of one-inch targets with precise control of various deposition parameters at a base pressure of ∼ 1x10−9 mbar. To explore the capability of the system, a set of thin films of HfO 2 , 5 % Ga 2 O 3 doped ZnO (GZO) and GZO/HfO 2 are deposited and the band offset of GZO/HfO 2 heterostructure is investigated by in-situ PES measurements using synchrotron radiation. The film surface is found to be contamination free, which demonstrates the capability of the set-up for in-situ PES studies. The Hf 4 f and Zn 3 d core level peaks along with valence band maxima positions are used to determine the valence band offset. The valence band offset is found to be 0.31 ± 0.08 eV, which is the first result reported on this heterostructure system. [ABSTRACT FROM AUTHOR]

Provides an overview of laser surface engineering (LSE) activities in India. Development of a process that involves tailoring the surface composition and or microstructure of the near surface region of a component without affecting the bulk; Suitability of lasers for a host of surface engineering activities such as LSE; Confinement of LSE-related activities to Government laboratories or research organizations.