Abstract
A semiconductor device includes first and second nitrogen-based semiconductor layers, a source electrode, a drain electrode, a gate electrode, and first and second stress modulation layers. The first nitrogen-based semiconductor layer has a first thickness. A band gap of the second nitrogen-based semiconductor layer is smaller than a band gap of the first nitrogen-based semiconductor layer to form a heterojunction therebetween. The second nitrogen-based semiconductor layer has a second thickness, and a ratio of the first thickness to the second thickness is in a range of 0.5 to 5. The first and second stress modulation layers stress the first and second drift regions of the second nitrogen-based semiconductor layer, respectively, thereby inducing first and second 2DHG regions within the first and second drift regions, respectively.