Effect of NO annealing on charge traps in oxide insulator and transition layer for 4H-SiC metal–oxide–semiconductor devices

The effect of nitric oxide（NO） annealing on charge traps in the oxide insulator and transition layer in n-type4H–Si C metal–oxide–semiconductor（MOS） devices has been investigated using the time-dependent bias stress（TDBS）,capacitance–voltage（C–V）,and secondary ion mass spectroscopy（SIMS）.It is revealed that two main categories of charge traps,near interface oxide traps（Nniot） and oxide traps（Not）,have different responses to the TDBS and C–V characteristics in NO-annealed and Ar-annealed samples.The Nniotare mainly responsible for the hysteresis occurring in the bidirectional C–V characteristics,which are very close to the semiconductor interface and can readily exchange charges with the inner semiconductor.However,Not is mainly responsible for the TDBS induced C–V shifts.Electrons tunneling into the Not are hardly released quickly when suffering TDBS,resulting in the problem of the threshold voltage stability.Compared with the Ar-annealed sample,Nniotcan be significantly suppressed by the NO annealing,but there is little improvement of Not.SIMS results demonstrate that the Nniotare distributed within the transition layer,which correlated with the existence of the excess silicon.During the NO annealing process,the excess Si atoms incorporate into nitrogen in the transition layer,allowing better relaxation of the interface strain and effectively reducing the width of the transition layer and the density of Nniot.

Electronic Theory of Thermodynamic Adhesion inMetal/Ceramic Systems

The thermodynamic adhesion between a metal and a ceramic crystal was believed to be the result of theelectron transfer from the metal into the cerainic crystal. From an electronic point of view, such an electrontransfer at the metal/ceramic interface may be represented by the tunnelling of the metal conduction electron into the ceramic bandgap. Theoretical analysis of the quantum tunnelling process at an intimate rnetal-semicon-ductor contact were performed . and the relationship between adhesion energies and Schottky barrier heights ofvarious metal/semiconductor or insulator interfaces was dcduced .

Three-dimensional flexible Au nanoparticles-decorated TiO_(2) nanotube arrays for photoelectrochemical biosensing

Controlling the charge transfer and thus enhancing the excitons’lifetime are the key to the realization of efficient photoelectrochemical(PEC)devices.Moreover,fabrication of flexible and collapsible sensors can greatly facilitate the implementation of smart PEC sensing devices into practical applications.Herein,we sagely designed and successfully fabricated three-dimensional flexible Au nanoparticles-decorated TiO_(2) nanotube arrays(Au@TiO2)for the efficient PEC biosensing of glucose.The Schottky barrier derived from the Au@TiO2 heterostructure efficiently separates the charge carriers at the junction interfaces,thus greatly increasing the concentration and lifetime of holes left in the valence band of TiO2.The separated holes further evidently generate the active hydroxyl radicals,which can specifically recognize and oxidize glucose.As a result,Au@TiO_(2) exhibits excellent photoelectric activity and selectivity,far superior to TiO_(2) without decorated Au nanoparticles.In addition,such asymmetric Au@TiO_(2) system has been proved to feature the intrinsic flexibility nature,since its PEC biosensing performance is almost unaffected under indirect light irradiation and serious tensile strain.