Nitridation of the SiO2/SiC Interface by N+ Implantation: Hall versus Field Effect Mobility in n-Channel Planar 4H-SiC MOSFETs

Francesco Moscatelli; Antonella Poggi; Sandro Solmi; Roberta Nipoti; Aldo Armigliato; Luca Belsito

doi:10.4028/www.scientific.net/MSF.645-648.491

Paper Titles

SiC and GaN MOS Interfaces – Similarities and Differences
p.473

Multiscale Modeling and Analysis of the Nitridation Effect of SiC/SiO₂ Interface
p.479

Dynamical Simulations of Dry Oxidation and NO Annealing of SiO₂/4H-SiC Interface on C-Face at 1500K: From First Principles
p.483

Preannealing Effect on Mobility of N-/Al-Coimplanted and Over-Oxidized 4H-SiC MOSFETs
p.487

Nitridation of the SiO₂/SiC Interface by N⁺ Implantation: Hall versus Field Effect Mobility in n-Channel Planar 4H-SiC MOSFETs
p.491

Systematic Investigation of Interface Properties in 4H-SiC MOS Structures Prepared by Over-Oxidation of Ion-Implanted Substrates
p.495

Effect of NO Annealing on 6H- and 4H-SiC MOS Interface States
p.499

Significant Decrease of the Interface State Density by NH₃ Plasma Pretreatment at 4H-SiC (000-1) Surface and its Bond Configuration
p.503

Improved Electrical Properties of SiC-MOS Interfaces by Thermal Oxidation of Plasma Nitrided 4H-SiC(0001) Surfaces
p.507

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Nitridation of the SiO₂/SiC Interface by N⁺ Implantation: Hall versus Field Effect Mobility in n-Channel Planar 4H-SiC MOSFETs

Abstract:

In this paper the electrical and structural characteristics of n-MOSFETs fabricated on 4H SiC with a process based on nitrogen (N) implantation in the channel region before the growth of the gate oxide are reported for low (5x1018 cm-3) and high (6x1019 cm-3) N concentration at the SiO2/SiC interface. The electron mobility and the free carrier concentration in the MOSFET channel were evaluated by Hall effect measurement. The MOSFETs with the higher N concentration had the best electrical characteristics in terms of threshold voltage and field effect mobility, in spite of a lowering of the electron mobility in the channel. The latter is a negative drawback of the fabrication process that probably can be ascribed to an incomplete recovery of the implantation damage or to a high density of interstitial N atoms present in the channel region. In fact, the MOSFETs with the superior electrical performances were fabricated with the higher N+ dose and the shorter thermal oxidation time. However, no evidence of extended defects, clusters or nano-particles in SiC at the interface with the gate oxide was found in every SiC MOSFETs devices observed by electron transmission microscopy