Development of SiC super-junction (SJ) device by deep trench-filling epitaxial growth

摘要

We have tried to fabricate a super junction (SJ) structure in SiC semiconductors by the trench-filling technique. After the deep trench formation by dry etching, epitaxial layer is grown over the trench surface. Doping profile of the embedded p-type epitaxial region between the trenches is evaluated by a scanning spreading resistance microscopy (SSRM). The SSRM result reveals that the doping profile is not uniform and there exists a low concentration region along the trench side-wall. Based on the SSRM result, two-dimensional device simulations are performed using pn-type test structures with the non-uniform SJ drift layer. The simulation result shows that blocking voltage of the test structure can be optimized and becomes comparable to that of the ideal one by adjusting the concentration design of the embedded layer to balance the total charge in SJ structure.