STEPWISE EQUILIBRATED GRADED GEXSI1-X BUFFER WITH VERY-LOW THREADING DISLOCATION DENSITY ON SI(001)

We have grown stepwise equilibrated graded GexSi1-x(x≤0.20) buffers with threading dislocation densities between 102 and 103cm-2 in their unstrained cap layers. The Ge content of the buffer was increased stepwise. The equilibrating treatment was performed as an in situ annealing in hydrogen at 1050°C after each and every layer of the buffer. Subsequently, the buffer was grown relaxed layer by relaxed layer. The extreme low threading dislocation density was present on the whole area of 4 in. wafers. © 1995 American Institute of Physics.