NORMALLY-OFF TYPE GaN-BASED FIELD EFFECT TRANSISTOR

摘要

PROBLEM TO BE SOLVED: To provide a normally-off type GaN-based FET having high gate voltage resistance and reduced on-resistance.

SOLUTION: A normally-off type GaN-based FET comprises: a channel layer 4 composed of a first type GaN-based semiconductor; a pair of electron supply layers 5 composed of a second type GaN-based semiconductor, which are separately formed of the channel layer each other; a gate insulating film 7 covering the channel layer between the electron supply layers; a source electrode and a drain electrode ohmically contacting the channel layer; and a gate electrode formed on the gate insulating film. The gate insulating film comprises a first and second insulating layers sequentially deposited on the channel layer. A first insulating layer 7a is composed of any of Si oxide, nitride, and oxynitride, and has a thickness of 5 nm or less. A second insulating layer 7b has a large ε×Eccompared with the first insulating layer, where ε represents a dielectric constant and Ecrepresents a breakdown electric field.

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