We fabricated narrow fins structures and non-planar MOSFETs like FinFETs and triple-gate MOSFETs using plasma doping with substrate heating under 350··, and measured their I-V characteristics. Fins and MOSFETs using low-temperature doping process show good current drivability and low subthreshold slope. However, without post high-temperature thermal annealing, this process could not avoid generating defects and traps as well as mobile protons on the gate and gate oxide interface and junctions, and therefore degraded device reliability. The results of ultra-small MOSFET research show possibility of new memory devices with these traps and ions in devices.

This letter describes a unique process for the preparation of high quality tantalum oxynitride (TaOxNy) with zirconium silicate (ZrSixOy) as an interfacial layer for use in gate dielectric applications. Compared with conventional native silicon oxide and oxynitride as an interfacial layer, tantalum oxynitride (TaOxNy) MOS capacitors using zirconium silicate (ZrSixOy) as an interfacial layer exhibit lower leakage current levels at the same equivalent oxide thickness. We were able to confirm TaOxNy/ZrSixOy stack structure by auger electron spectroscopy (AES) and transmission electron microscope (TEM) analysis. The estimated dielectric constant of TaOxNy and ZrSixOywere approximately 67 and 7, respectively. The zirconium silicate is a promising interfacial layer for future high-k gate dielectric applications.

In this paper, we report a process for the preparation of high quality amorphous tantalum oxynitride (TaOxNy) via ammonia annealing of Ta2O5 followed by wet reoxidation for use in gate dielectric applications. Compared with tantalum oxide(Ta2O5), a significant improvement in the dielectric constant was obtained by the ammonia treatment followed by light reoxidation in a wet ambient. We confirmed nitrogen incorporation in the tantalum oxynitride (TaOxNy) by Auger Electron Spectroscopy. By optimizing the nitridation and reoxidation process, we obtained an equivalent oxide thickness of less than 1.6nm and a leakage current of less than 10mA/cm2 at -1.5V. Compared with NH3 nitridation, nitridation of Ta2O5 in ND3 improve charge trapping and charge-to-breakdown characteristics of tantalum oxynitride.