Atomic layer etching of silicon by using a low-angle forward reflected ar neutral beam

Summary form only given. Atomic layer etching (ALET) can be an indispensable method in the fabrication of future devices such as nano-scale devices, quantum devices et al., because current etch technology utilizing reactive ion etching does not have precise etch rate controllability and tends to damage the surface of the devices physically and electrically due to the use of energetic reactive ions to achieve vertical etch profiles. Therefore, many studies on ALET of Si have been reported in recent years to develop a technique to etch materials layer-by-layer. But, these previous methods may show charging due to the charged particles such as positive ions and photons generated in the plasma. Therefore, in this study, the ALET of Si was carried out for the first time using an Ar neutral beam instead of the Ar⁺ ion beam to avoid charge-related damage during the desorption of halide and its ALET characteristics of Si by Cl₂ were investigated. Especially, the ALET of Si having different orientation of (100) and (111) were investigated to understand the silicon etch rate per cycle. Also, the study of ALET mechanisms, variation of surface roughness has been investigated. By supplying Cl ₂ and Ar neutrals higher than critical doses, the constant etch rate of a monolayer per cycle (1.36 and 1.57 Aring/cycle for Si (100) and Si (111), respectively) and the lowest surface roughness of 1.45 Aring close to the reference sample could be obtained regardless of Cl₂ pressure and Ar neutral beam irradiation time. The step height divided by the total number of ALET cycles yielded the etch rate per cycle. An atomic force microscope (AFM) was used to measure the surface roughness. Also, a scanning electron microscope (SEM) was used to observe as-etched Si profiles