is vapor deposited on the p ingaas layer 101 in association with the opening 323 defined by above etching afterwards the mask 150 is removed as shown in fig4 a 12 and 4 b 12 finally a bonding pad 330 and a wiring portion 331 provided between the electrode 324 and the bonding pad 330 are formed on the second passivation film 144 and part of the electrode 324 from the electrode 324 to the polyimide filler body 301 by vapor deposition as shown in fig4 a 13 and 4 b 13 the concave portion 280 formed by etching the semiconductor layer structure for the under electrode and the channel shaped trenches 121 and 282 provided on the sides of the mesa stripe 124 are isolated from and become independent of each other as described above thus the present embodiment can be designed so that the protruding comers described as the drawback of the conventional example will not appear in the shapes of the two trenches 121 and 282 owing to the above design the present embodiment results in a structure wherein the overhang extended with the ingaas p contact layer 101 employed in the conventional example as the mask is not formed either the overhang does not definitely appear in an actually formed device and hence an extremely uniform wafer process can be implemented discussion was made even to the influence of the trench dividing semiconductor layer 281.