Tailoring of Optical Properties of Alumina films deposited by High Vacuum CVD (HV-CVD)

Abstract

The deposition of amorphous alumina (Al2O3) films on four inch wafers with high deposition rate (up to 50 nm/min) by an advanced HV-CVD technique is discussed. Amorphous nature of the films is confirmed by X-ray diffraction. Refractive index of the deposited alumina can be adjusted in the large range (1.3-1.62@633 nm) by varying the substrate temperate during the deposition. The films are highly transparent. The density and stoichiometry of the deposits are also influenced by deposition conditions. Presence of -OH groups is observed in some cases.

Combination of Electron or Laser Beam Irradiation with High Vacuum Chemical Vapor Deposition (HV-CVD) of Al2O3 for in-situ Local Structuring on Wafer Scale Substrate

“…Deposition can be achieved by thermal decomposition of the precursor when heating the wafer at 250°C-700°C. These four inch wafer homogeneous deposits are discussed elsewhere (10). Here laser and electron beam assisted deposition are discussed.…”

“…Aluminum isopropoxide (Al(OC 3 H 7 ) 3 ) is ECS Transactions, 25 (8) 1087-1092 (2009) 10.1149/1.3207710 © The Electrochemical Society used as precursor. The detailed description of the reactor and the precursor delivery system can be found in (10,11). Precursor was evaporated by heating to 140°C degrees in a reservoir connected to the reactor, no carrier gas was used.…”

“…This observation could be explained by the higher film nucleation density due to electron bombardment. However, such small grain size has also been observed during the thermal growth under certain conditions (10). Currently, it is believed that thermal effect of the electron beam irradiation (temperature increase of the substrate surface) plays an important role.…”

“…The highest growth rate achieved is about 10 nm/min, which is of the same order of magnitude as for thermal deposition of alumina with Al-isopropoxide. (10).…”

Optically transparent and durable Al2O3 coatings for harsh environments by ultra short pulsed laser deposition

“…Other versatile production techniques for optical thin films include chemical vapour deposition (CVD) [9][10][11][12] and atomic layer deposition (ALD) [12,13] which are both based on the transport of material in a gaseous phase to reaction chamber and allowing chemical reactions to take place to deposit film on a selected surface. The ALD processing method differs from otherwise similar CVD by allowing conformal atomic level control over the deposition process.…”