Structural control in atomic layer deposited hafnium oxide thin films through vertical cavity surface-emitting laser (VCSEL)-Based ultra-rapid heating

Abstract

HfO2 thin films were formed by plasma-enhanced atomic layer deposition (PEALD) using TDMAHf precursor as a Hf source and oxygen plasma as an oxygen source. Rapid annealing assisted by a 980 nm wavelength vertical cavity surface-emitting laser (VCSEL) was employed to assess the dielectric properties of the HfO2 thin films, compared to furnace annealing. Operational power and time of VCSEL was precisely controlled by computational simulation. In addition to decreased thickness of the interfacial layer, rapid annealing enabled reduced leakage current density as annealing temperature increased due to suppression of crystallization, resulting from the extremely short time duration of 0.98 s-8.14 s. Cross-sectional microstructures exhibited incomplete grain boundary formation of the rapidly annealed HfO2 thin film. VCSEL-based rapid annealing was verified to be an efficient process to enhance the dielectric characteristics of high-k dielectric oxide films.