| abstract |
A source electrode ( 5 ), a drain electrode ( 6 ) and a T-shaped gate electrode ( 9 ) are formed on a GaN-based semiconductor layer ( 3,4 ) to form a transistor. An insulating film ( 10,11 ) covering the T-shaped gate electrode ( 9 ) is formed. A property of the transistor is evaluated to obtain an evaluation result. A film type, a film thickness or a dielectric constant of the insulating film ( 10,11 ) is adjusted in accordance with the evaluation result to make a property of the transistor close to a target property. |