Papers by Keyword: Phosphorus Ion Implantation

Abstract: The effect of phosphorus (P) on the electrical properties of the 4H-SiC / SiO₂ interface was investigated. Phosphorus was introduced by surface-near ion implantation with varying ion energy and dose prior to thermal oxidation. Secondary ion mass spectrometry revealed that only part of the implanted P followed the oxidation front to the interface. A negative flatband shift due to residual P in the oxide was found from C-V measurements. Conductance method measurements revealed a significant reduction of density of interface traps D_it with energy E_C - E_it > 0.3 V for P⁺-implanted samples with [P]_interface = 1.5 10¹⁸ cm^-3 in the SiC layer at the interface.

Abstract: Phosphorous implanted n+/p diodes have been included in the masks for manufacturing n-MOSFET devices and processed in the same way of source/drain regions. The diode junctions were made by a P+ implantation at 300°C and a post implantation annealing at 1300°C. The diode emitter area was protected by 0.6 m thick CVD oxide during the processing of the MOSFET gate oxide. Three gate oxide processes were taken into account: two of them include a N implantation before a wet oxidation, while the third one was a standard oxidation. Considering the effect on the n+/p diodes, the main difference among the processes were the wet thermal oxidation time that ranged between 180 and 480 min at a temperature of 1100°C. The diode current-voltage characteristics show similar forward but different reverse curves in the temperature range of 25-290°C. Differences in reverse bias voltage as a function of the measurement temperature have been analyzed and are related to the different gate oxidation time. A correlation between the shortest oxidation time and the lower leakage current is presented.