Influence of Threading Dislocations on Lifetime of Gate Thermal Oxide

Kensaku Yamamoto; M. Nagaya; H. Watanabe; E. Okuno; T. Yamamoto; S. Onda

doi:10.4028/www.scientific.net/MSF.717-720.477

Paper Titles

Detection of Mobile Ions in the Presence of Charge Trapping in SiC MOS Devices
p.461

Two-Way Tunneling Model of Oxide Trap Charging and Discharging in SiC MOSFETs
p.465

Peak Degradation of Heavy-Ion Induced Transient Currents in 6H-SiC MOS Capacitors
p.469

Low Frequency Noise in 4H-SiC Lateral JFET Structures
p.473

Influence of Threading Dislocations on Lifetime of Gate Thermal Oxide
p.477

Doping-Induced Lattice Mismatch and Misorientation in 4H-SiC Crystals
p.481

Strain Build-Up, Swelling and Stacking Fault Formation in Implanted 4H-SiC
p.485

High Resolution X-Ray Diffraction (HRXRD) Studies of the Initial Stages of PVT-Growth of 4H-SiC Crystals
p.489

On the Stability of 3C-SiC Single Crystals at High Temperatures
p.493

HomeMaterials Science ForumMaterials Science Forum Vols. 717-720Influence of Threading Dislocations on Lifetime of...

Influence of Threading Dislocations on Lifetime of Gate Thermal Oxide

Abstract:

The reliability of gate oxides is a fundamental issue for realizing SiC MOSFETs. Many reports said that crystal defects shorten the lifetime of the gate oxide. And, epi defects, the basal plane dislocations and threading screw dislocations (TSD) are considered killer defects. However, because of the high TSD density of commercial SiC wafers, the exact relationship between other kinds of dislocations with lifetime has not been revealed. On the other hand, RAF wafers that we developed have low TSD density, so it is easy to evaluate the relationship between other kinds of dislocations and lifetime. By using RAF wafers, in this study, we clarified the relationship between the lifetime of the gate oxide and crystal defects. We fabricated MOS diodes and measured their lifetimes by TDDB (Time Dependent Dielectric Breakdown) measurement. The breakdown points were defined by the photo-emission method. Finally, we classified the defects by TEM (Transmission Electron Microscopy). As the results, it was clarified that threading edge dislocation (TED) decreases the lifetime as does TSD, which earlier reports said. The lifetime of the gate oxide area, in which a TED is included, was shorter by one order of magnitude than a wear-out breakdown. And, the TSD was two orders.