Abstract
Characterizing electric fields in semiconductor devices using electric
field-induced second-harmonic generation (EFISHG) has opened new
opportunities for an advanced device design. However, this new
technique still has challenges due to the interference between
background second-harmonic generation (SHG) and EFISHG generated
light. We demonstrate that interference effects can effectively be
eliminated during EFISHG measurements by focusing the laser from the
transparent substrate side of a GaN PN diode, enabling straightforward
quantitative electric field analysis, in contrast to PN junction
interface side measurements. A model based on wave generation and
propagation is proposed and highlights the incoherence between
background SHG and EFISHG light. This incoherence may be attributed to
the depth of focus of the incident laser and phase mismatch between
incident and SHG light.
Funder
Engineering and Physical Sciences
Research Council
China Scholarship Council