Improved High Precision Dopant/Carrier Concentration Profiling with Corona-Charge Non-Contact C-V (CnCV)

Abstract

We report significant advancements in corona-based non-contact capacitance-voltage (CnCV) metrology recently developed for comprehensive C-V characterization of SiC and other wide bandgap semiconductors. The technique answers the industries needs for nondestructive, cost-effective C-V dopant monitoring for material and device development and manufacturing control. Excellent precision and matching to mercury probe CV is demonstrated for SiC, Ga2O3, GaN and AlGaN/GaN structures over a concentration range from 1014cm-3 to 2x1019cm-3. The emphasis in the present work is on improvement of CnCV in dopant depth profiling resolution and measurement throughout. This is achieved with a variable charge method that in-situ adjusts corona charging increments in response to changes in dopant concentration. Results are presented for multi-layer epitaxial SiC and for 2DEG in AlGaN/GaN HEMT structures. The latter represents an extreme case of high-low concentration profiling with a transition from 1020electrons/cm-3 in the 2D electron gas to a fully depleted well and dopant concentration in the 1015cm-3 range.