Trap Assisted Gas Sensing Mechanism in MISiC Capacitors

Alton B. Horsfall; Ming Hung Weng; Rajat Mahapatra; Nicolas G. Wright

doi:10.4028/www.scientific.net/MSF.556-557.621

Paper Titles

Reduction of Traps and Improvement of Carrier Lifetime in SiC Epilayer by Ion Implantation
p.603

Selenium and Tellurium Double Donors in SiC
p.607

Use of Graphite Cap to Reduce Unwanted Post-Implantation Annealing Effects in SiC
p.611

Dynamical Simulation of SiO₂/4H-SiC(0001) Interface Oxidation Process: from First-Principles
p.615

Trap Assisted Gas Sensing Mechanism in MISiC Capacitors
p.621

4H-SiC Metal-Oxide-Semiconductor (MOS) Capacitors Fabricated by Oxidation in a Tungsten Lamp Furnace in Combination with a Microwave Plasma and Subsequent Deposition of Al₂O₃
p.627

A Comparative Study of Surface Passivation on SiC BJTs with High Current Gain
p.631

Acceleration Factors in Acceleration Life Test of Thermal Oxides on 4H-SiC Wafers
p.635

Characterization of MOS Capacitors Fabricated on n-type 4H-SiC Implanted with Nitrogen at High Dose
p.639

HomeMaterials Science ForumMaterials Science Forum Vols. 556-557Trap Assisted Gas Sensing Mechanism in MISiC...

Trap Assisted Gas Sensing Mechanism in MISiC Capacitors

Abstract:

We present the variation of trap assisted conduction current through a dielectric stack comprising TiO2 and SiO2 on SiC as a function of both temperature and hydrogen gas concentration. We show that the current can be modeled by the use of a single barrier height across the temperature range of interest (>300oC ambient). Upon exposure to hydrogen gas, this barrier height is reduced from 0.405 to 0.325eV, whilst the density of traps in the bulk of the TiO2 remains unaffected. We conclude that the formation of a charge dipole layer under the palladium contact is responsible for this change in barrier height, as has been observed in Schottky diode sensor structures. Further, sensing the gas concentration by monitoring of the trap assisted conduction current appears not to be influenced by the existence of interfacial traps, offering the chance to fabricate low drift sensors for deployment in extreme environments.