Investigation of post-annealing effects for normally-off GaN metal-oxide semiconductor heterojunction field-effect transistors with thin AlN barrier layer

Autor: Imai Akifumi, Tatsuro Watahiki, Hidetoshi Koyama, Mikio Yamamuka, Takuma Nanjo
Rok vydání: 2019
Předmět:
Zdroj: Japanese Journal of Applied Physics. 58:SBBD09
ISSN: 1347-4065
0021-4922
DOI: 10.7567/1347-4065/aafb5f
Popis: The effects of post-annealing processes for normally-off GaN metal-oxide semiconductor heterojunction field-effect transistors (MOS-HFETs) with a thin AlN barrier layer are investigated. These annealing processes are post-deposition annealing (PDA) after oxide deposition, post-metallization annealing (PMA) after gate metallization, and positive-bias annealing (PBA) after wafer processes. PMA and PBA are effective in enhancing the drain current density and threshold voltage shift. The most effective method is PBA and the obtained threshold voltage and drain current density are +3.0 V and 0.7 A mm−1, respectively. This is attributed to improvements in interfacial trap states which is confirmed by an investigation of the frequency dependence of capacitance–voltage characteristics.
Databáze: OpenAIRE