Recent Advancement in Noncontact Wafer Level Electrical Characterization for WBG Technologies

A breakthrough high throughput WBG semiconductor dopant monitoring method has recently been introduced based on the novel concept of sweeping the electrical bias by near UV illumination-induced photoneutralization of corona charge. As originally discovered for 4H-SiC, the doping determination can be realized using the value of the photoneutralization time constant. In the present work this procedure is tested for β-Ga 2 O 3 with a larger energy gap of 4.8eV, using a correspondingly deeper UV range. Such deep UV application to the AlGaN/GaN HEMT structure resulted in the development of a new measurement principle capable of increasing the HEMT wafer measurement throughput 10 times compared to previous corona noncontact C-V metrology. The new principle involves a linear illumination-induced corona charge bias sweep. Combined with surface voltage monitoring, it provides a means for fast and precise determination of the pinch-off voltage, V P , the AlGaN electrical thickness, and the 2D electron gas density.