ICP-induced defects in GaN characterized by capacitance analysis

The defects induced by inductively coupled plasma reactive ion etching (ICP-RIE) on a Si-doped gallium nitride (GaN:Si) surface have been analyzed. According to the capacitance analysis, the interfacial states density after the ICP-etching process may be higher than 5.4 × 1012 eV−1 cm−2, compared to around 1.5 × 1011 eV−1 cm−2 of non-ICP-treated samples. After the ICP-etching process, three kinds of interfacial states density are observed and characterized at different annealing parameters. After the annealing process, the ICP-induced defects could be reduced more than one order of magnitude in both N2 and H2 ambient. The H2 ambient shows a better behavior in removing ICP-induced defects at a temperature around 500 °C, and the interfacial states density around 2.2 × 1011 eV−1 cm−2can be achieved. At a temperature higher than 600 °C, the N2 ambient provides a much more stable interfacial states behavior than the H2 ambient.