Electrical and Chemical Studies on Al2O3 Passivation Activation Process

Al2O3 deposited using Atomic layer Deposition (ALD) technique is known as an excellent material for p-type silicon surface passivation. However a post-deposition annealing step is needed to make the passivation effective. Thanks to coupled electrical measurements (capacitance and photoconductance) and chemical analyses (X-ray Photoelectron Spectroscopy (XPS) and Secondary Ion Mass Spectrometry (SIMS)) carried out on the same p-type Cz silicon sample, a closer explanation of this activation process is given. The presence of hydrogen and oxygen is correlated to the evolution of the electrical parameters and the minority carrier lifetime for 0 to 60 min 450 °C annealing.