Strain control of Si and Si _1-y C _y layers in Si/Si _1-y C _y /Si(100) heterostructures

Strain engineering has become indispensable for electron and hole mobility improvement of ULSIs as scaling down of device dimension. In order to realize the high performance strained Si layer, it is very important to create a defect-free relaxed Si _1-x-y Ge _x C _y layer. In the previous work, it was found that, by stripe-shape patterning unstrained Si cap layer/compressive-strained Si _1-x Ge _x layer/Si(100) heterostructure, the strain of the cap Si layer becomes tensile and resistivity of both n- and p-type cap Si layers becomes smaller at the narrower stripe width below 250 nm, although change of the resistivity for the unstrained Si is negligibly small. On the other hand, it was found that electrical inactive P and B atoms are generated by tensile-strain in heavy P and B doped region. In the present work, in-situ heavy C doping in Si growth and compressive-strained Si layer formation by stripe-shape patterning unstrained Si cap layer/tensile-strained Si _1-y C _y layer/Si(100) are investigated. We have demonstrated that lattice constant and Raman shifts of Si-Si and Si-C modes of Si _1-y C _y are normalized by C fraction obtained from XPS C1s peak at 283.3 eV that is substitutional C fraction. By stripe-shape patterning of the Si(10 nm)/Si0.98C0.02(20-60 nm)/Si(100) heterostructure, compressive-strained Si cap layer is realized.