Reliability characterization of advanced oxynitride gate dielectrics for ULSI MOSFET application.

摘要

The evolution of ULSI MOSFET technology has occurred primarily as a result of the increased number of devices on a chip. This has been accomplished by the aggressive scaling of feature size and gate oxide thickness of MOSFET. As a result, the reliability of the gate dielectrics becomes a more important issue. Moreover, use of aggressive plasma-based processes has become commonplace in modern integrated circuit manufacturing, requiring more reliable gate dielectrics against the plasma-induced damage.; This research work is initially divided into four parts; (1) plasma-induced charging damage in MOSFETs with NO-based oxynitride, (2) gate-induced drain leakage in MOSFETs with NO-based oxynitride, (3) soft breakdown characteristics in ultra-thin gate dielectrics, and (4) characterization of MOSFETs with oxynitride gate dielectrics fabricated at high pressure and low temperature.; Prior research has focused on the fabrication and development of NO-annealed oxynitridation. This research concentrates on reliability characterization of MOSFET with the oxynitride gate dielectrics formed by two advanced oxynitridation techniques with anneal of thermal oxide in NO-ambient and/or growth of oxynitride in high pressure N{dollar}sb2{dollar}O ambient, resulting in the formation of reliable gate dielectrics with low thermal budget against hot carrier reliability, plasma-induced charging damage, dielectric breakdown and boron penetration. However, it is found that nitrogen peak distribution around SiO{dollar}sb2{dollar}/Si-substrate interface degraded gate-induced drain leakage in N-MOSFETs and gate dielectric hardness in P-MOSFETs. In N-MOSFETs, nitrogen distribution underneath SiO{dollar}sb2{dollar} enhances the gate-induced drain leakage after hot carrier stress due to the enhanced band-to-defect tunneling through mid-gap traps at the buried nitrogen rich layer. In P-MOSFETs, boron accumulation within the dielectrics due to the nitrogen peak at SiO{dollar}sb2{dollar}/Si-substrate results in dielectric degradation. Nitrogen peak at top surface of the dielectrics was implemented with high pressure N{dollar}sb2{dollar}O oxynitridation in this research, suggesting one of the promising oxynitridation techniques for the future MOSFET technology.