Spray coated aluminum oxide thin film for P-type crystalline silicon surface passivation

Aluminum oxide (Al2O3) thin films deposited by spray coating process is evaluated for surface passivation of silicon. The fixed oxide charge (Qf) and interface state density (Dit) are found to be -4.2 × 1012 cm-2 and 3.5 × 1011 eV-1cm-2, which demonstrates its potential for silicon surface passivation. High breakdown electric field up to 10.2 MV/cm was obtained for 13nm Al2O3 film which indicates the high quality of the Al2O3 film. Effective lifetime (τeff) of 502 μs and corresponding SRV of 28 cm/s was obtained on float-zone wafers passivated by these films. The film also shows excellent thermal stability. XPS analysis reveals that the film is stoichiometric.