METHOD FOR DEPOSITING A STRAIN RELAXED GRADED BUFFER LAYER OF SILICON GERMANIUM ON A SURFACE OF A SUBSTRATE

A method for depositing a strain relaxed graded buffer layer of silicon germanium on a surface of a substrate, the surface consisting of silicon and the buffer layer having an increasing content of germanium up to a final content, the method comprising conducting GeCl4 and SiH2Cl2 during a first and a second stage over the surface of the substrate at a deposition temperature of not less than 800 °C; growing the buffer layer with a grade rate that is less than 10 % Ge / µm; and growing the buffer layer with a growth rate that is not less than 0.1 µm / min during the first stage and that is less than 0.1 µm / min during the second stage.