| Summary: | 博士 === 國立交通大學 === 電子工程系所 === 95 === To continue down-scaling CMOS technology, traditional insulator layer - SiO2 will face the physical limitation - large gate leakage current. In addition, traditional poly-Si gate encounters several inherent limitations, such as poly-Si depletion, boron penetration, and high resistivity. Therefore, new insulator and gate material technologies will become urgent for very large scale integration (VLSI) technology in the future years. Recently, metal-gate/high-k process technologies become one of the most important researches in the semiconductor industry. In this dissertation, we will investigate the application of several high-k dielectric and metal gate process technologies.
First of all, we will study the application of HfSiON dielectric with HfSix and IrxSi full silicidation (FUSI) metal gates in n-MOSFETs and p-MOSFETs, respectively. Although HfSiON has smaller dielectric constant than HfO2, it has better thermal stability. Besides, using HfSix and IrxSi FUSI metal gates can obtain better thermal stability than using pure metal gates, and also can reduce the effective work function shifts due to Fermi-level pinning effect. These results indicate that integrating HfSiON with HfSix and IrxSi FUSI metal gates can achieve dual metal gates development in CMOS technology.
Next, we will study another high-k dielectric HfLaON with metal nitride TaN gate in n-MOS application. HfLaON has good thermal stability as HfSiON, but it has the advantage of higher k value. Moreover, TaN also has similarly good thermal stability. Integrating HfLaON with TaN gate will provide the appropriate effective work function in n-MOS application.
Finally, the application of high-�� LaAlO3 dielectric into low-temperature poly-Si thin-film transistors (TFTs) combining with low work function Yb metal gates was investigated. Good TFT performance was achieved - such as a high drive current and low threshold voltage due to the down-scaling effective oxide thickness (EOT) provided by the high-k dielectric. In addition, the good performance was achieved without hydrogen passivation or special crystallization steps. These results suggest that the Yb/LaAlO3 TFTs can meet the device requirements for system-on-panel (SOP) applications.
|
|---|
