Pulsed Rapid Thermal Annealing as a Low Thermal Budget Semiconductor Fabrication Process

Abstract

Thermal annealing is required in the fabrication of many semiconductor devices. A proper annealing condition, e.g., temperature, atmosphere, and time, can improve the device performance, e.g., by reducing defect densities in bulk films and at interfaces. In addition, the annealing step can generate new structures in previously deposited thin films for various new functions. However, when the annealing condition is improper, e.g., the temperature is too high or the annealing time is too long, the device performance can deteriorate or dysfunction due to damage to the composing material, structure, or even the substrate. The thermal budget is critical in the thermal annealing step.Pulsed rapid thermal annealing (PRTA), which exposes the sample to repeated cycles of short-period heating and cooling, is a low thermal budget process. In this presentation, the principle of PRTA is presented. Examples of using PRTA in the crystallization of amorphous silicon on the glass substrate to polycrystalline thin films for thin film transistors (TFTs) and solar cells, improving high-k gate dielectric properties for MOS capacitors and solid state incandescent light emitting devices (SSI-LEDs), and preparation of nanocrystals embedded high-k structure for nonvolatile memories will be shown (1-4). Limitations of PRTA and possible improvements will be discussed. Kuo and P. M. Kozlowski, Appl. Phys. Lett., 69(8), 1092-1094 (1996).Kuo, C.-H. Lin, and M. Zhu, IEEE Photovoltaic Specialist Conf. PVSC 35, 3698-3701 (2010).Y. Kuo and C. H. Lin, ECS 237th Meeting # 130648, May 10-15, 2020.Y. Kuo, ECS 227th Meeting # 47306 (1333), May 24-28, 2015.