利用Ｎ２Ｏ氧化物及疊型非晶矽結構(ＳＡＳ)抑制ｐ＋多晶矽閘中Ｂｏｒｏｎ的穿透效應

Abstract

在本論文中，包含二種氧化物之四種型式的多晶矽閘結構被提及來抑制ｐ 型金氧半電容中硼離子的穿透，其中有Ｎ２Ｏ氧化物之疊型非晶矽結構能 有效抑制硼的穿透．由於疊型非晶矽結構提供曲折且較長的晶界和疊層界 面有效阻止硼離子和氟離子擴散到氧化物和矽基座．此外，Ｎ２Ｏ提供的 氮離子也能阻止硼離子和氟離子擴散．因此Ｎ２Ｏ氧化物之疊型非晶矽結 構有一些好處反應在電性上．這些包含高的崩潰電場，大的崩潰電荷，和 低的電子捕捉．其界面陷阱密度也很低．更甚者由硼離子的穿透所引起Ｖ ＦＢ電壓的漂移即使經過３０分鐘退火在Ｎ２Ｏ氧化物之疊型非晶矽結構 仍不明顯．所以Ｎ２Ｏ氧化物之疊型非晶矽結構抑制硼的穿透上是很穩定 的結構． In this thesis, four types of poly-Si gate structure with two types of gate oxide were investigated to suppress the boron penetration in p+ poly-Si gate pMOSFET's. Both N2O oxide and stacked α-Si structure can effectively suppress the boron penetration. Due to the stacked α-Si structure, most curved paths of grain boundary and the interface of stacked layer effectively retard fluorine and boron diffusion through the oxide and into the substrate. In addition, due to N2O ambient it offer the distribution of N atoms in the bulk which also retard the diffusion of boron andfluorine. Thus the SAS structure with N2O oxide has some advantage in the electric characteristics . Thus includes a higher breakdown field, a large breakdown charge, and lower trapping. Moreover the interface state is almost very low.Furthermore, the boron penetration induced the increase in the flat-band voltage shift is no significant in the SAS and N2O sample after annealing for 10-30 min. Consequently, the SAS/N2O is the most reliable structure to suppress the boron penetration.