Nitride semiconductor device and method of manufacturing the same
Provided is a nitride semiconductor device with high reliability and high flexibility in design and manufacture of the device. The nitride semiconductor device comprises a seed crystal portion ( 11 ) formed on a sapphire substrate ( 10 ) and having a mask ( 12 ) on one side surface thereof, and a GaN layer ( 15 ) grown on the sapphire substrate ( 10 ) and the seed crystal portion ( 11 ) through epitaxial lateral overgrowth. The GaN layer ( 15 ) is grown only from an exposed side surface of the seed crystal portion ( 11 ) which is not covered with the mask ( 12 ), so the lateral growth of the GaN layer ( 15 ) is asymmetrically carried out. Thereby, a meeting portion ( 32 ) is formed in the vicinity of a boundary between the seed crystal portion ( 11 ) and the mask ( 12 ) in a thickness direction of the GaN layer ( 15 ). Therefore, as the meeting portion ( 32 ) is formed in a position away from the center between the adjacent seed crystal portions ( 11 ) in a direction parallel to a surface of the substrate, a width W L of a lateral growth region is larger with respect to a pitch W P of the seed crystal potion ( 11 ), compared with conventional configurations.
1. A method of manufacturing a nitride semiconductor device, comprising the steps of:
forming a seed crystal layer made of a nitride compound semiconductor on a substrate;
forming a plurality of masks having a shape with an end and the other end of different thicknesses in a laminated direction in stripes on the seed crystal layer; and
forming a crystal layer made of a nitride compound semiconductor on the seed crystal layer with the masks in between.
2. A method of manufacturing a nitride semiconductor device according to claim 1 , wherein
a lateral growth reaion with a width greater than or equal to 0.5 times W p is formed on the seed crystal, wherein the sum of the width of the mask and the width of a region between adjacent masks is W P .
3. A method of manufacturing a nitride semiconductor device according to claim 2 , further comprising the step of:
forming a laser stripe portion so as to correspond to the lateral growth region, after the crystal layer is formed.
4. A method of manufacturing a nitride semiconductor device according to claim 2 , further comprising the step of:
forming a source region, a gate region and a drain region so as to correspond to the lateral growth region, after the crystal layer is formed.
5. A method of manufacturing a nitride semiconductor device according to claim 1 , wherein
the crystal layer is formed through metal organic chemical vapor deposition (MOCVD).