REPRODUCIBLE GROWTH OF INASXSB1-X/INSB STRAINED-LAYER SUPERLATTICE PHOTODIODES BY LOW-PRESSURE MOCVD

Reproducible growth of InAsxSb1-x/InSb strained-layer superlattice photodiodes by low pressure metalorganic chemical vapor deposition (MOCVD) has resulted from the use of Zn doped InAsxSb1-x step-graded buffer layers. These photodiodes show improved performance with response to 10 mum and detectivities of 4 X 10(9) cm Hz1/2/W at 6 mum. Dislocation formation in InAsxSb1-x buffer layers grown on InSb substrates by MOCVD is shown to be reproducibly enhanced by p-type doping at levels exceeding the intrinsic carrier concentration at 475-degrees-C using diethylzinc. Carrier concentrations up to 6 x 10(18) cm-3 were obtained. The Zn doped buffer layers have proven to be reproducibly crack free for InAsxSb1-x step graded buffer layers with a final composition of x = 0.12 lattice matched to a strained layer superlattice (SLS) with an average composition of x = 0.09.