COMPOUND SEMICONDUCTOR DEVICE AND MANUFACTURING METHOD OF THE SAME

摘要

PROBLEM TO BE SOLVED: To achieve a compound semiconductor device which has no deterioration in withstanding voltage and no instability in an operation in a comparatively simple constitution, and which successfully achieves normally-off by obtaining a sufficiently high threshold voltage to thereby achieve high reliability and high withstanding voltage.SOLUTION: A compound semiconductor device comprises in each compound semiconductor layer: a first layer 3; a second layer 4 which is formed above the first layer 3 and has bandgap wider than that of the first layer 3; a third layer 5a which is formed above the second layer 4 and has a p-type conductivity type; a gate electrode 11 formed above the second layer 4 via the third layer 5a; a fourth layer 6 which is formed above the second layer 4 so as to contact the third layer 5a and has bandgap wider than that of the second layer 4; and a fifth layer 7 which is formed above the fourth layer 6 so as to contact the third layer 5a and has bandgap narrower than that of the fourth layer 6.