Characteristics of GaN Thin Films Using Magnetron Sputtering System

Abstract

The paper presents a polycrystalline GaN thin film with a hexagonal wurtzite structure under the optimized sputtering conditions of 40 W RF power, 5 mT working pressure, using pure nitrogen gas with a substrate temperature of 700˚C. The study examines the effects of surface disorders and incorporates it in the thin films characteristics. A radio frequency (RF) Ultra High Vacuum (UHV) Magnetron Sputtering System has been used for the deposition of Gallium Nitride (GaN) on silicon, sapphire and glass substrates with different parameters. The power is varied from 40 W to 50 W, and the pressure from 4 mT to 15 mT. The effects of the RF sputtering powers and gas pressures on the structural properties are investigated experimentally. Sputtering at a lower RF power of 15 W does increase the N atomic percentage, however the deposition rate is substantially slower and the films are amorphous. GaN deposited on both silicon and sapphire wafer resulted in thin films close to stoichiometric once the N 2 concentration is 60% or higher. It is also observed that the substrate cooling/heating effects improve the quality of the thin films with fewer defects present at the surface of the GaN epi-structure.

Substrates Effect on the Phase Transition of GaN Thin Films by Sputter Deposition

“…However, we easily grow sole dominant c-ZB phase GaN on Si(100) by RF sputtering. This might be attributed to the speculation of Kim et al 8 . They suggested that the impact of the hyperthermal species impinging on the surface of growing films resulted in the internal compressive stress that was sufficiently large to stabilize the nonequilibrium c-ZB phase of GaN.…”

“…Only a few reports have been published discussing the effects of the growth conditions and substrate materials on the GaN thin film properties by RF sputtering. 2 34 -5687 8 Among them, Kim et al 8 studied GaN thin film on Si(100) by RF sputtering of a GaN target in pure nitrogen atmosphere at (10mTorr -30mTorr) and discussed the N2 gas pressure effect on the wurtzite (h-WZ) to zine-blende (c-ZB) phase transition in GaN thin films. Miyazerki et al 4 studied the GaN films deposited onto various substrates by reactive sputtering of gallium target in nitrogen gas at pressure from 0.08 to 2.70 Pa.…”

Growth Optimization of Nonpolar Al0.7Sc0.3N(112¯0)/Al2O3(11¯02) Thin Films Using Reactive Magnetron Sputter Epitaxy

“…As the first step, process temperature and process gas flow were both optimized simultaneously to account for possible interdependencies. Previous studies of sputtered nitrides, for example, AlScN [ 45 ] or GaN, [ 46 ] have shown these two parameters to be the most influence on the crystalline quality.…”

Effects in the Optical and Structural Properties Caused by Mg or Zn Doping of GaN Films Grown via Radio-Frequency Magnetron Sputtering Using Laboratory-Prepared Targets

“…An N 2 flow was used during sputtering, as well as a RF power of 50 W and a gas pressure of 25 × 10 −3 Torr were kept during the sputtering deposition. It also required a longer deposition time of 8 h to grow a thick layer [20,22]. Additionally, silicon (100) substrates were used to remove organic residues, along with the conventional cleaning of solvents and solutions.…”

“…The c peak broadening of the X-ray diffraction patterns could be produced for two reasons. First, this deposition technique does not produce good crystalline quality in the layers at room temperature; however, when the substrate is heated, the crystalline quality in the films could get better [22]. Second, the presence of nano-crystallites hinders the crystalline quality [16].…”