Metalorganic vapor phase epitaxy (MOVPE) growth and characterization of III-nitride heterostructures for application in electronic devices

In this thesis we have demonstrated Metalorganic Vapor Phase Epitaxy (MOVPE) of single layer GaN and various III-Nitride heterostructures for application in electronic devices. The MOVPE technique was successfully applied to both a horizontal system and a vertical close-coupled showerhead (CCS) systems. A new gas mixing system was designed specifically for GaN growth. Our unintentionally doped (UID) GaN growth by CCS MOVPE had a mobility of 326 cm2/Vs, background carrier concentration of 4 x 1016 cm -3 and total TD density from 2-6 x 109 cm -2. Growth rate, mobility and carrier concentration were uniform to less than +/-5% across the full 2'' wafer.; High resistance (HR) GaN templates for AlGaN/GaN Hetrojunction Field Effect Transistor (HFET) applications were grown using CCS MOVPE. The GaN sheet resistance was tuned using final nucleation layer (NL) annealing temperature and NL thickness. Using an annealing temperature of 1033°C and NL thickness of 26 nm, GaN with sheet resistance of 1010 O/sq was achieved. AlGaN/GaN HFET layers grown using HR GaN templates show low interface roughness (<10A), high RT 2DEG mobility (∼1300 cm2/Vs) and uniformity of <5%. Devices using the HR GaN template show improvement in both ft and fmax from 7 and 12 GHz for the UID template to 12 and 35 GHz using HR template. These results show a clear advantage in device performance for HR template layers.; The horizontal MOVPE technique was used to grow AlN/GaN MIS-type heterostructures with AlN thickness between 3 nm and 30 nm. By decreasing the ammonia flow during AlN growth (lower V/III ratio), surface and interface quality were greatly improved with a corresponding improvement in electrical properties. The best RT mobility, for both optimal V/III and thickness, was 1015 cm 2/Vs with a sheet charge of 1.1 x 1013 cm -2. Electrical characterization of MIS diodes fabricated from the AlN/GaN layers show that a 2DEG is formed very near the AlN/GaN interface. The results show the possibility to use MOVPE for growth of device quality AlN/GaN MIS-type heterostructures.; The Photo Electrochemical (PEC) etching technique was applied to the single GaN layers grown in this study. Whisker formation observed under these conditions was used to measure the dislocation density in the single GaN layers. Additionally, whisker formation was reduced under PEC etch conditions that use a Hg(Xe) light source.