摘要
With the rapid development of semiconductor technology, the feature size of MOSFETs has been aggressively scaled down. The thickness of gate di- electric reduces accordingly, which causes significant gate leakage current via direct tunneling. To suppress the leakage current, high-k materials are highly de- manded to replace the conventional gate dielectrics, such as SiO2 and SiON, due to the fact that its higher dielectric constant can ensure a larger physical thick- ness at the same EOT and reduce the leakage current accordingly. Among the alternative high-k materi- als, HfO2 is a promising candidate with a relatively high dielectric constant, good thermal stability and a relatively large bandgap. However, previous work demonstrated that there are large density defects in HfO2, which is a few orders of magnitude higher than that in conventional SIO2. This limits its application in MOSFETs due to the excessive low-field leakage current induced by trap-assisted tunneling, which will increase the static power dissipation in integrated cir- cuits. For theoretical modeling establishment and fast material assessment, the energy distribution of elec- tron traps across the HfO2 becomes essential. How- ever, the detailed information is still largely missing.
With the rapid development of semiconductor technology, the feature size of MOSFETs has been aggressively scaled down. The thickness of gate di- electric reduces accordingly, which causes significant gate leakage current via direct tunneling. To suppress the leakage current, high-k materials are highly de- manded to replace the conventional gate dielectrics, such as SiO2 and SiON, due to the fact that its higher dielectric constant can ensure a larger physical thick- ness at the same EOT and reduce the leakage current accordingly. Among the alternative high-k materi- als, HfO2 is a promising candidate with a relatively high dielectric constant, good thermal stability and a relatively large bandgap. However, previous work demonstrated that there are large density defects in HfO2, which is a few orders of magnitude higher than that in conventional SIO2. This limits its application in MOSFETs due to the excessive low-field leakage current induced by trap-assisted tunneling, which will increase the static power dissipation in integrated cir- cuits. For theoretical modeling establishment and fast material assessment, the energy distribution of elec- tron traps across the HfO2 becomes essential. How- ever, the detailed information is still largely missing.
基金
Supported by the National Basic Research Program of China under Grant No 2011CBA00606, the National Natural Science Foundation of China under Grant Nos 61334002, 61106106 and 61474091, the Opening Project of Science and Technology on Reliability Physics and Application Technology of Electronic Component Laboratory under Grant No ZHD201206, the New Ex- periment Development Funds for Xidian University, and the Fundamental Research Funds for the Central Universities under Grant No K5051325002.
