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论文类型：期刊论文

发表时间：2020-05-30

发表刊物：APPLIED SURFACE SCIENCE

收录刊物：EI、SCIE

卷号：513

ISSN号：0169-4332

关键字：4H-SiC; MOS capacitor; Density of interface traps; Bias temperature instability; Synergistic effects; Post-oxidation annealing

摘要：Interface properties and bias temperature instability (BTI) determine the performance and stability of SiC metaloxide semiconductor (MOS) devices. In this work, we propose an electron cyclotron resonance microwave nitrogen-oxygen (N-O) mixed plasma post-oxidation annealing (POA) process to improve the interface properties and BTI of 4H-SiC MOS capacitors. Results showed that the N-O mixed plasma POA reduces the density of interface traps, maintains the stability of the flat band voltage (V-fb) hysteresis under four successive cycles of positive bias temperature stress (PBTS) and negative bias temperature stress (NBTS) at 423 K, and significantly reduces the V(fb )hysteresis under alternating PBTS and NBTS at 100 K. The oxide traps remarkably decreased to 2.27 x 10(12) cm(-2) after N-O mixed plasma POA. The related passivation and improvement mechanisms were further studied by secondary ion mass spectroscopy, X-ray photoelectron spectroscopy, and density functional theory calculations. The synergistic effects of highly reactive N and O plasma promoted the considerable absorption of N at the interface and prevented further oxidation of the SiC substrate. We also elaborate on the effects of N, O, and N-O plasma on the elimination and passivation of O vacancy defects, C-related defects (SiOxCy and C dimer), and Si interstitial defects and discuss implications of the simultaneous suppression of electron and hole trapping.