Paper TF-TuA4
Electrical Properties of Plasma-Enhanced Atomic Layer Deposition HfO₂/HfO_xN_y/HfO₂ Gate Oxide

Tuesday, October 21, 2008, 2:40 pm, Room 302

Nitrogen incorporation produces several benefits in the performance of high k gate oxides. However, since too much nitrogen incorporation at the interface of gate dielectric results in device degradation, the proper amount of nitrogen incorporation with precise depth profile control is desirable. In this study, the microstructure and electrical properties of plasma enhanced atomic layer deposition (PE-ALD) HfO₂ gate oxides with nitrided middle layer (HfO₂/HfO_xN_y/HfO₂) were investigated. The nitridation of the middle layer was carried out by two different in situ processes; PE-ALD using N/O mixture plasma (denoted as HfON) and PE-ALD HfN using hydrogen plasma followed by oxidation during the consequent HfO₂ deposition (denoted as HfONO). Significantly better electrical properties were obtained for HfONO than HfON in terms of hysteresis, equivalent oxide thickness, and reliability. In addition, high nitrogen incorporation up to 10 at% with improved thermal stability was achieved for HfONO sample. The experimental results will be discussed based on the atomic bonding configurations analyzed by X-ray photoemission spectroscopy.