Wet thermal annealing effect on TaN/HfO2/Ge metal - Oxide - Semiconductor capacitors with and without a GeO2 passivation layer
- 物理技术－已发表论文 
Wet thermal annealing effects on the properties of TaN/HfO2/Ge metal - oxide - semiconductor (MOS) structures with and without a GeO 2 passivation layer are investigated. The physical and the electrical properties are characterized by X-ray photoemission spectroscopy, high-resolution transmission electron microscopy, capacitance - voltage (C - V) and current - voltage characteristics. It is demonstrated that wet thermal annealing at relatively higher temperature such as 550 掳C can lead to Ge incorporation in HfO2 and the partial crystallization of HfO 2, which should be responsible for the serious degradation of the electrical characteristics of the TaN/HfO2/Ge MOS capacitors. However, wet thermal annealing at 400 掳C can decrease the GeOx interlayer thickness at the HfO2/Ge interface, resulting in a significant reduction of the interface states and a smaller effective oxide thickness, along with the introduction of a positive charge in the dielectrics due to the hydrolyzable property of GeOx in the wet ambient. The pre-growth of a thin GeO2 passivation layer can effectively suppress the interface states and improve the C - V characteristics for the as-prepared HfO2 gated Ge MOS capacitors, but it also dissembles the benefits of wet thermal annealing to a certain extent. 漏 2012 Chinese Physical Society and IOP Publishing Ltd.