Evaluation of dopant removal to design innovative LGADs: Measurements and simulations

The development of innovative Low-Gain Avalanche Diode architectures has required the characterisation of dopant removal at high initial concentrations. In this contribution, dopant removal is investigated using sheet resistance measurements on dedicated van der Pauw test structures. Donor removal coefficients are extracted for NPLUS implants at initial concentrations exceeding 10$^{18}$ cm$^{−3}$. The acceptor removal coefficient is also directly extracted for the PPLUS implant and validated by means of TCAD simulations, in which a SIMS-based process simulation scaled according to the extracted coefficient reproduces the measured evolution of the sheet resistance with irradiation. The results show that donor removal proceeds approximately a factor of 2–3 faster than acceptor removal, also at high initial dopant concentrations.