Sub-nanometer heating depth of atomic layer annealing

Abstract

Conventional annealing techniques face tremendous challenges in nanoscale fabrication. For example, the heating depth of conventional annealing techniques is much greater than the critical dimension of nanoscale devices, resulting in excessive thermal budget and so degradation of device performance. In this study, the atomic layer annealing (ALA) technique of a sub-nanometer heating depth is demonstrated. ALA is an in-situ plasma treatment applied in the process of atomic layer deposition (ALD), resulting in delivery of energy to the surface of as-deposited thin films from the plasma. The ALA treatment introduced into each ALD cycle leads to significant enhancement of crystallinity, film density, and dielectric constant, as well as considerable suppression of leakage current and threading dislocation densities, of the AlN layer. These improvements of the AlN properties was degraded significantly with an increase of the cycle spacing of the ALA treatment in the ALD process, indicating the heating depth of the ALA technique is below 5 atomic layers. The result indicates that the ALA process of precise sub-nanometer heating depth plays a critical role to achieve high-quality nanoscale materials and devices.