Embedded silicon germanium (eSiGe) technologies for 45nm nodes and beyond

This paper reviews main technologies of embedded silicon germanium (eSiGe) for 45 nm node and beyond .There are three key techniques and an item to be considered carefully as follows. The first technique is a low temperature of epitaxial growth at 550degC to suppress stacking faults in eSiGe layer. The second one is a controlling of recess shape for eSiGe. Sigma(Sigma)-shaped recess is applied, because the strain force on the channel of MOSFET is increased effectively by narrowing spacing between source and drain. The third one is to apply particular surface pre-cleaning treatment before the epitaxial growth, to get the excellent SiGe crystallinity. The final item to be considered carefully is boron concentration in eSiGe, because excessive boron compensates the strain in eSiGe as well as carbon. Finally We demonstrated the Ion = 0.795 mA/mum@Ioff = 100 nA/mum using above key techniques and an item.