低溫微波退火在互補式金氧半場效電晶體之研究

Abstract

由於未來電晶體元件尺寸繼續縮小，源極與汲極的掺雜擴散與活化是很重要的議題，在這個博士論文中，新穎的微波退火(Microwave annealing)被研究在低溫環境。微波退火也與傳統高溫退火做比較。首先我們在界面層、金屬閘極和高介電係數介電層在微波退火下之研究，也將微波退火應用於掺雜活化。金屬閘極之部份，金屬閘極TiN搭配介電層SiO2之電容結構使用微波退火；藉由低溫微波退火能抑制金屬閘極TiN之功函數漂移。金屬閘極TiN與TaN搭配高介電係數介電層HfO2之電容結構使用微波退火，等效氧化層厚度在高溫退火下會增加，使用低溫微波退火可以抑制等效氧化層厚度增加。最後我們將微波退火應用於金屬閘極TiN與TaN搭配高介電係數介電層HfO2在電晶體結構上，由於微波退火能抑制掺雜擴散與抑制等效氧化層厚度增加，短通道效應能有效被抑制。

Due to the scaling of devices in the future, the dopant diffusion and activation will be key issues. In this thesis, a new annealing technology of microwave annealing (MWA) was investigated in low-temperature annealing environment. MWA and conventional high-temperature annealing are also compared. At first, we investigated the electrical characterization of interfacial layer, metal gate and high-k by using MWA, we also investigate the dopant activation by using MWA. In the part of metal gate, the TiN gate electrode were prepared on SiO2, in which the work function shift of TiN is suppressed due to the low-temperature process. The capacitance-voltage characteristics of the MOS gate stacks, TiN/ HfO¬2¬ and TaN/ HfO2, after different annealing methods are also discussed. The increasing of equivalent oxide thickness (EOT) in the MOS devices after dopant activation processing can be eliminated by using low-temperature MWA. The Id-VG characteristics of the MOSFET devices with TiN/ HfO¬2¬ and TaN/ HfO2 after different annealing methods are discussed. The short channel effects in MOSFETs annealed by MWA can be improved due to the suppression of dopant diffusion and EOT increasing. In addition, the interfacial layer (IL) thickness growth can be also suppressed by MWA.