锗预非晶化注入对镍硅(NiSi)金属栅功函数的影响研究

随着超大规模集成电路技术的发展,CMOS器件的制备过程需要同时引入金属栅和超浅结等新的先进工艺技术,因此各种新工艺的兼容性研究具有重要意义.本文研究了超浅结工艺中使用的锗预非晶化对镍硅(NiSi)金属栅功函数的影响.对具有不同剂量Ge注入的NiSi金属栅MOS电容样品的研究表明,锗预非晶化采用的Ge注入对NiSi金属栅的功函数影响很小(小于0.03eV),而且Ge注入也不会导致氧化层中固定电荷以及氧化层和硅衬底之间界面态的增加.这些结果表明,在自对准的先进CMOS工艺中,NiSi金属栅工艺和锗预非晶化超浅结工艺可以互相兼容.     

Corner effects in double-gate/gate-all-around MOSFETs

Two kinds of corner effects existing in double-gate (DG) and gate-all-around (GAA) MOSFETs have been investigated by three-dimensional (3D) and two-dimensional (2D) simulations. It is found that the corner effect caused by conterminous gates, which is usually deemed to deteriorate the transistor performance, does not always play a negative role in GAA transistors. It can suppress the leakage current of transistors with low channel doping, though it will enhance the leakage current at high channel doping. The study of another kind of corner effect, which exists in the corner at the bottom of the silicon pillar of DG/GAA vertical MOSFETs, indicates that the D-top structure with drain on the top of the device pillar of vertical transistor shows great advantage due to lower leakage current and better DIBL (drain induced barrier lowering) effect immunity than the S-top structure with source on the top of the device pillar. Therefore the D-top structure is more suitable when the requirement in leakage current and short channel character is critical.