Metal organic vapor phase epitaxy growth and electrical characterization of high-resistivity and lattice-mismatched indium-arsenic-phosphorus and aluminum-indium-arsenic-phosphorus buffer layers for indium arsenide and indium phosphide device application

In this thesis, we investigate the metal organic vapor phase epitaxy (MOVPE) growth and material characterization of metamorphic lattice mismatched InAsP and AlInAsP epilayers on InP substrate. The work was motivated by the need to develop a resistive buffer layer structure having lattice constant between InP substrate and InAs device layer for high performance InAs-based heterostructure electronic devices. Epitaxial growth and characterization of InAsP and AlInAsP having lattice constant between InP and InAs is scant in the existing literature. To our knowledge this is the first systematic investigation on the growth and electrical characterization of InAsP and AlInAsP alloys having lattice constant between InP and InAs. The question to be answered in this thesis is this: what is the highest resistivity one can achieve under optimized growth conditions for metamorphic buffer layers. In assessing the morphological, structural, compositional, electrical, transport and optical properties, we have used a variety of material characterization tools including Nomarski microscopy, double-crystal X-ray diffractometer, transmission electron microscopy, Rutherford backscattering spectroscopy, Hall-effect measurement and photoreflectance.;Under optimized growth condition, we achieved sheet resistance 2.8x10 5O/sq and 4.8x104O/sq for single layer InAs0.44P0.56 (0.5mum) and step-graded InAs0.75 P0.25[InAs0.42P/0.58 (0.075 mum/0.5pmum) layers respectively. A new bowing parameter for InAsyP1-y of -0.22 eV is found based on photoreflectance measurement. When 0.5microm-thick Al0.11In0.89As.62P.38 is grown, we obtain sheet resistance and sheet carrier concentration of 7.76x10 5O/sq and 7.92x109cm-2, respectively. This opens interesting possibilities for realizing high-performance metamorphic Field-Effect Transistors (FETs) based on strained InAs or InAsyP 1-y (0.5< y<0.75) channel and AlInAsP buffer.;High sheet resistance, lattice-mismatch AlxIn1-xAs yP1-y buffer layers were also grown on InP in the lattice constant range of 5.93A--5.98A between the lattice constant of InP and InAs. Under optimized growth conditions, we achieved sheet resistance from 2.45x104O/sq to 2.03x 106O/sq and sheet carrier concentration of 8.06x1010 cm-2 to 3.79x109cm-2 respectively for 0.5mum single layer AlxIn1-xAsyP1-y. The sheet resistance is about 7 times higher than the corresponding metamorphic InAsP on InP layers having the same lattice constant, thus making AlInAsP a suitable buffer layer for InAs-based electronic devices on InP substrates.