The application of chemical beam epitaxy to indium phosphide based materials and devices.

Abstract

The application of Chemical Beam Epitaxy (CBE) to InP based devices was investigated with particular attention on the optimization of bulk material and heterointerface quality. Statistical techniques were employed during the optimization of InGaAs and InP to explore the interactions between electron mobility and surface morphology for each material system. The characterization of InGaAsP focused on the temperature sensitivity of the lattice matching conditions. Characterization of the InAlAs, grown with TriMethylAmine Alane (TMAA), showed acceptable levels of carbon and oxygen, validating the usefulness of the novel TMAA precursor. The heterointerface quality was investigated by Spectroscopic Ellipsometry (SE) and low temperature Photoluminescence (PL) of quantum wells. The SE results indicated that InP on InGaAs had significant arsenic contamination, while InGaAs on InP did not show any phosphorus contamination. PL was used to optimize the switching sequence at the interface by examining energy shifts, peak widths and signal intensities. A number of Multi-Quantum Well Separate Confinement Heterostructure (MQW-SCH) lasers were grown to test the quality of the interfaces. It was found that the threshold current density of the lasers did track with the quality of the interfaces as determined by PL. The InAlAs/InP interface was characterized by capacitance voltage techniques to determine the density of interface states. It was found that quality of the InAlAs/InP interface was not dependent on the switching sequence used. InGaAs and InP channel High Electron Mobility Transistors (HEMTs) were grown by CBE and fabricated with sub-micron gates. It was found that although delta doping worked well with InGaAs channel devices, channel mobilities were very poor in delta doped InP channel HEMTs due to poor electron confinement. Excellent device results were obtained with-both InP and InGaAs channel HEMTs. Results from CBE grown lasers, HBTs, HETs and RTDs are included to demonstrate the ability of CBE to produce high quality electronic and opto-electronic devices. CBE's flexibility in producing a wide variety of high quality materials and devices should make it an attractive tool for both research and production environments.