Precise Depth Control and Low-Damage Atomic-Layer Etching of HfO[sub 2] using BCl[sub 3] and Ar Neutral Beam

The etch characteristics of by atomic-layer etching (ALET) were investigated using a neutral beam. The effect of ALET on surface modification and etch-depth control was also examined. Self-limited etching of could be obtained using ALET. This was attributed to the absorption of by the Langmuir isotherm during the absorption stage and the vaporization of hafnium-chlorides/boron oxychlorides formed on the surface during the desorption stage. In addition, the surface composition of was not altered by etching during ALET.