Atomic Layer Deposition of Titanium Oxide-Based Films for Semiconductor Applications—Effects of Precursor and Operating Conditions

• Published in: Materials Vol. 16; no. 16; p. 5522
• Main Authors: Matkivskyi, Vladyslav, Leiviskä, Oskari, Wenner, Sigurd, Liu, Hanchen, Vähänissi, Ville, Savin, Hele, Di Sabatino, Marisa, Tranell, Gabriella
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.08.2023; MDPI
• Subjects: ALD precursors; Aluminum oxide; Annealing; atomic layer deposition; Atomic layer epitaxy; Carrier lifetime; Gases; Metal oxides; Minority carriers; passivation films; Passivity; Photovoltaic cells; Precursors; Solar cells; Spectrum analysis; Temperature; Thin films; Titanium; Titanium chlorides; titanium oxide; Titanium oxides; Transmission electron microscopy
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma16165522

Two widely used atomic layer deposition precursors, Tetrakis (dimethylamido) titanium (TDMA-Ti) and titanium tetrachloride (TiCl4), were investigated for use in the deposition of TiOx-based thin films as a passivating contact material for solar cells. This study revealed that both precursors are suited to similar deposition temperatures (150 °C). Post-deposition annealing plays a major role in optimising the titanium oxide (TiOx) film passivation properties, improving minority carrier lifetime (τeff) by more than 200 µs. Aluminium oxide deposited together with titanium oxide (AlOy/TiOx) reduced the sheet resistance by 40% compared with pure TiOx. It was also revealed that the passivation quality of the (AlOy/TiOx) stack depends on the precursor and ratio of AlOy to TiOx deposition cycles.