A preliminary study of MIS diodes with nm-thin GaAs-oxide layers

Autor: Shoushin Hashimoto, Tomoyuki Sugimura, Kouichi Iiyama, Yuki Kasai, Takayuki Katsui, Saburo Takamiya, Tatsutoshi Tsuzuku, Takao Inokuma
Rok vydání: 1999
Předmět:
Zdroj: Solid-State Electronics. 43:1571-1576
ISSN: 0038-1101
Popis: Direct oxidation of GaAs wafers, by using UV and ozone oxidation system, was performed to form nm-thin GaAs-oxide layers. Composition of the oxidized layer, studied by XPS analysis, shows depth-dependent atomic percentage of the Ga, As, and O. Surface flatness and thickness of the oxide were investigated with AFM. The oxide thickness is nearly proportional to square root of the UV and ozone process time. Using the oxidized layer as the insulator, Ni/insulator/n-GaAs MIS diodes were fabricated, and compared with Ni/n-GaAs Schottky diodes of their gate leakage currents. Very clear leakage current suppression effect of the insulating layer is observed, which is controllable by controlling the UV and ozone process time. However, the suppression effect is much smaller than that theoretically estimated for a MIS diode with perfectly uniform SiO2. Theoretical equations to estimate effect of a nm-thin insulating layer on current-voltage relation of a MIS diode are shown in the appendix.
Databáze: OpenAIRE