Two-dimensional characterization of ion-implantation damage in GaN Schottky contacts using scanning internal photoemission microscopy

Abstract

Nitrogen-ion-implantation damage on GaN has been clearly visualized using scanning internal photoemission microscopy. Ni Schottky contacts were formed on selectively N-ion-implanted n-GaN surfaces at 80 keV with an ion dose of 1 × 1014 or 1 × 1015 cm−2, and a photocurrent was detected by focusing and scanning a laser beam over the contacts. We found that the photocurrent decreased in the implanted regions due to an increase in the Schottky barrier and carrier depletion. Photocurrent maps showed that the induced damage did not spread from the implanted regions within the spatial resolution of the equipment. We confirmed that this method is a powerful tool for mapping implanted highly resistive regions.

Mapping of n‐GaN Schottky Contacts With Wavy Surface Morphology Using Scanning Internal Photoemission Microscopy

“…Therefore, in this study, we conducted two‐dimensional characterization of the effect of surface morphology on the electrical properties of low‐carrier thick n‐GaN layers via scanning internal photoemission microscopy (SIPM). SIPM was originally developed by the authors, which can visualize local variations in electrical characteristics of metal/semiconductor interfaces . Nanoscale, two‐dimensional characterization using a conductive atomic force microscope has been reported for Pt/GaN Schottky contacts .…”

Mapping of contactless photoelectrochemical etched GaN Schottky contacts using scanning internal photoemission microscopy—difference in electrolytes

“…20,21) We have reported mapping results for the effect of ion-implanted, ICP-etched, and neutral beam etched damages on Schottky contacts on GaN and SiC. [22][23][24][25] These types of manufacturing processes cause relatively severe non-uniform damage on the surface of the semiconductor. In the past, we have characterized much finer surface damage from the processes.…”

Characterization of peripheries of n-GaN Schottky contacts using scanning internal photoemission microscopy

“…We originally developed scanning internal photoemission microscopy (SIPM) to map electrical characteristics of metal/ semiconductor interfaces. 13,14) We have demonstrated the mapping of characteristics for interfacial reactions; degradation under applied voltage stress; and surface damage for Schottky contacts on Si, 13) GaAs, [14][15][16] GaN, [17][18][19][20][21] indiumgallium-zinc oxide, 22) and SiC. 17,[23][24][25] The advantage of this method is that local variation in the electrical characteristics can be clearly visualized.…”