Digital Control of SiO₂−TiO₂ Mixed-Metal Oxides by Pulsed PECVD

Abstract

Pulsed plasma enhanced chemical vapor deposition (PECVD) was used to deliver digital control of SiO(2), TiO(2), and SiO(2)-TiO(2) composites at room temperature. Alloy formation was investigated by maintaining constant delivery of TiCl(4) while varying the SiCl(4) flow. Film composition was assessed by spectroscopic ellipsometry, XPS, and FTIR. It is shown that the alloy composition and refractive index can be tuned continuously over a broad range using pulsed PECVD. The two precursors were found to be highly compatible, with the alloy growth rate simply reflecting the sum of the contributions from the two individual precursors. Digital control over both thickness and composition was demonstrated through the production of antireflection (AR) coatings for crystalline silicon. AR coatings were synthesized on the basis of optimized designs, and in each case the measured optical performance was found to be in excellent agreement with model predictions. The average reflectance across the visible spectrum was reduced from 39% for uncoated wafers to 2.5% for the three-layer AR coating.

Preparation of Janus Titanium Dioxide Particles via Ultraviolet Irradiation of Pickering Emulsions

“…For all TiO 2 particles, a peak at 700 cm −1 corresponding to the stretching vibration of Ti–O was present. For all s‐TiO 2 particles, asymmetric stretching (1104 cm −1 ), symmetric stretching (800 cm −1 ), and rocking modes (474 cm −1 ) of Si–O–Si groups were present . In addition, the peak at 953 cm −1 corresponding to Si–O–Ti stretching modes was also present for all s‐TiO 2 particles.…”

Solar Photovoltaic Energy Harnessing

“…Use of backside contact by SunPower to avoid shadowing effects (Mulligan and Swanson, 2003), anti-reflection coating (Rowlette and Wolden, 2009) and plasmonic techniques (Atwater and Polman, 2010), especially in thin silicon wafers (also common to other PV technologies), are some of the processing tricks used by various manufacturers to increase the efficiency of solar cells. A good reference on issues related to silicon PV can be found in Goetzberger et al (2003).…”

Influence of pulse power amplitude on plasma properties and film deposition in high power pulsed plasma enhanced chemical vapor deposition

“…For this, a fundamental understanding of how the plasma chemistry and thereby the deposition process can be a) Electronic mail: henke@ifm.liu.se controlled by the plasma discharge is first needed. A step towards such an understanding is the finding that by pulsing the plasma in "standard" PECVD, i.e., by switching it on and off, and carefully selecting the precursor chemistry, selflimiting growth, similar to atomic layer deposition, of metal oxides [8][9][10][11] and recently also sulphides, 12 can be achieved without pulsing the precursor gases. The pulsed nature of HiPP-PECVD could potentially further advance this type of PECVD.…”