Dislocation-free silicon epitaxial layers lightly doped with boron have been grown on heavily boron-doped silicon layer without any buffer layers (p/p+silicon substrate) after eliminating misfit dislocations in the heavily boron doped (p+) silicon layer. To remove misfit dislocations in the p+ layer, a undoped protection ring had been used.
NMOSFET's were fabricated on this substrate as well as the conventional p/p+ silicon substrate for comparison. The devices on the dislocation-free p/p+ silicon substrate show superior characteristics to those on the conventional substrate in MOSFET off-current, n+/p junction leakage current and gate oxide leakage current. Also the Si-$SiO_2$ interface property is improved due to the reduction of wafer surface roughness and this decreases the fixed charge density.
The devices on dislocation-free substrate have higher uniformity than those on the conventional substrate.
