Insight on defects mechanically introduced by nanoindentation in 4H-SiC p-n diode

We investigate defects in 4H-SiC p-n junction diodes introduced trough nanoindentation procedure. A nanoindentation load range between 3 mN and 15 mN was explored. Scanning Electron Microscopy and Transmission Electron Microscopy analysis are adopted for the morphological and crystallographic investigation of defects; electrical characterisations of junction diodes are performed to investigate the conduction mechanism, both at RT and versus measurement temperature. Electrical parameters such ideality factor, leakage current and series resistance, are extracted for the processed diodes and compared to virgin one. Activation energy of about 1.7 eV and 0.2 eV are extracted for defects in virgin and in mechanically processed devices, respectively. Electro-optical characterisation is performed adopting Emission Microscopy measurements evidencing a diffuse photons emission in the visible range from the full area in virgin device and an emission in the visible and in the near infrared ranges from nanoindentation sites in processed devices. Performed analysis evidenced both extended and point defects are mechanically introduced. Thanks to the performed experiment, a promising way is paved for the defects engineering, in a microscale spatially defined position, in end of processing devices.