Precise control of lattice strain in carbon-doped GaAs by indium co-doping for reliable AlGaAs/GaAs heterojunction bipolar transistors

Abstract Indium/carbon co-doping in GaAs by metalorganic chemical vapor deposition using carbon tetrachloride (CCl 4 ) and trimethylindium (TMI) is investigated in order to precisely control lattice strain. The lattice mismatch produced by C and H atoms is revealed quantitatively. It is found that the In-incorporation rate into GaAs is reduced by the interaction between CCl 4 and TMI in the gas phase. Lattice strain in C-doped GaAs layers is shown to be controlled independent of hole concentration as a result of In co-doping. It is confirmed that In co-doping does not deteriorate the crystal qualities of C-doped GaAs layers, such as the mobility and minority electron lifetime. Indium co-doping brings about a significant improvement in the device lifetime of AlGaAs/GaAs heterojunction bipolar transistors (HBTs) by relaxing the strain in the base layer.