A new technique for local deep level transient spectroscopy (DLTS) imaging using super-higher-order scanning nonlinear dielectric microscopy is proposed. Using this technique. SiCVSiC structure samples with different post oxidation annealing conditions were measured. We observed that the local DLTS signal decreases with post oxidation annealing (POA), which agrees with the well-known phenomena that POA reduces trap density. Furthermore, obtained local DLTS images had dark and bright areas, which is considered to show the trap distribution at/near SiCVSiC interface.

We measured AlGaN/GaN heterostructure using scanning nonlinear dielectric microscopy (SNDM) [1], which can measure both carrier and polarization profile in AlGaN/GaN heterostructure. As a result, GaN spontaneous polarization and AlGaN polarization which is sum of spontaneous polarization and piezoelectric polarization were clearly distinguished. Two dimensional electron gas (2DEG) was observed at the AlGaN/GaN interface. This results show that SNDM is useful method for evaluation of 2DEG profile and polarization profile in AlGaN/GaN heterostructure.

Evaluation techniques for semiconductor devices are keys for device development with low cost and short time to market. Especially, dopant and depletion layer distribution in devices is a critical electrical property that needs to be evaluated. Super-higher-order nonlinear dielectric microscopy (SHOSNDM) is one of the promising techniques for semiconductor device evaluation. We developed a method for imaging detailed dopant distribution and depletion layers in semiconductor devices using SHO-SNDM. As a demonstration, a cross-section of a SiC power semiconductor device was measured by this method and detailed dopant distribution and depletion layer distributions were imaged.