Berlin 2015 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 81: Heterostructures and interfaces

HL 81.12: Talk

Thursday, March 19, 2015, 18:00–18:15, EW 201

Thermal and optical defect spectroscopy in AlInN/AlN/GaN hetero-structures on Si(111) — •Aqdas Fariza, Hartmut Witte, Jonas Hennig, Jürgen Bläsing, Armin Dadgar, Andre Strittmatter, and Alois Krost — Institute of Experimental Physics, Otto von Guericke University Magdeburg, Magdeburg, Germany

AlInN/GaN based high electron mobility transistors (HEMTs) are ideally suited for high power applications because of high electron concentrations and mobility. Additionally, the growth of AlInN/GaN HEMTs on Si-substrates has many advantages to reduce device costs. But, the presence of defects and traps constitutes a major problem which leads to leakage currents and other degradation effects. Some traps have been assigned to cause these phenomena but still there is lacking information for structures on Si substrates. Temperature dependent I-V- and C-V-characteristics were carried out as well as thermal and optical admittance spectroscopy and photo-induced current transient spectroscopy for trap characterization both in InAlN/AlN/GaN/Si(111) hetero-structures and in GaN/Si(111) buffer layers. In both sample types identical trap emissions between 60 meV and 350 meV were found. All methods demonstrate strong optical quenching effects and non-shifting peak positions when changing the emission rates caused by the presence of mid gap traps in GaN. In contrast, the InAlN layers yield a shallow thermally activated resistivity up to 40 meV.