Selective annealing of Al₂O₃/silicon interface by using an Nd³⁺: YAG laser with a wavelength of 532 nm

In this report, a selective interface laser annealing (SILA) process is applied to the atomic-layer-deposited Al₂O₃ film/p-type silicon interface using an Nd³⁺: YAG laser with a wave-length of 532 nm. The absorptivity of the laser wavelength confirms a full absorption of the laser power to the Al₂O₃/Si interface without any loss through the Al₂O₃ film, which results in a successful selective annealing of the interface. Compared with conventional forming gas annealing (FGA), the SILA is found to build a thinner SiO₂ interface layer and lead to a less reduction of capacitance. It is also revealed that the laser-annealed sample exhibits a surface blister density of 31 counts/mm² which is much lower than the value of 250 counts/mm² obtained from FGA. The suppression of the surface blister is attributed to the much shorter processing time of lasing (<60 ns) that results in reducing the interaction time between H⁺ and Si–H bonding and desorption of gaseous hydrogen. It is demonstrated that the ultra-short SILA processing is a promising method to enhance the interface properties of oxide/semiconductor with efficient processing time.