Study towards integration of In0.53Ga0.47As on 300 mm Si for CMOS sub-7 nm node: Development of thin graded InxGa1−xAs buffers on GaAs

High-quality InxGa1−xAs layers with indium composition between 0.46 and 0.50 have been grown in a 300 mm industrial MOVPE reactor using ≤1 μm thin InxGa1−xAs buffers on 2″ GaAs substrates. Aggressive grading of 3.7 to 3.8% misfit/μm, fast growth rates in the range of 0.2-2.2 nm/s and low growth temperatures of 530 °C and 450 °C were used. AFM reveals a significant difference in root mean square surface roughness of 3.6 nm (530 °C) versus 15.5 nm (450 °C). Cross-section TEM analysis shows that for both temperatures threading dislocations are effectively confined to the buffer region. However, at 450 °C phase separation is observed in the upper part of the structure. From plan-view TEM threading dislocation densities as low as 1×105 cm−2 and 4.5×105 cm−2 are estimated for growth at 530 °C and 450 °C, respectively.