Electron capture and emission properties of interface states in thermally oxidized and NO-annealed SiO2/4H-SiC

Postoxidation annealing in nitric oxide (NO) results in a significant reduction of electronic states at SiO2/4H-SiC interfaces. Measurements of electron trapping dynamics at interface states in both thermally oxidized and NO annealed SiO2/4H-SiC interfaces were performed using constant-capacitance deep level transient spectroscopy (CCDLTS) and double-CCDLTS. We show that the interface state density in as-oxidized samples consists of overlapping distributions of electron traps that have distinctly different capture cross sections. The dominant trap distributions, centered at Ec−0.24 eV with σ∼7×10−19 cm2, and at Ec−0.46 eV with σ∼4×10−17 cm2 are passivated by NO annealing. The remaining interface states all have capture cross sections in the range 10−19−10−21 cm2.

[1]  Andre Stesmans,et al.  Shallow electron traps at the 4H–SiC/SiO2 interface , 2000 .

[2]  Einar Ö. Sveinbjörnsson,et al.  Interfaces between 4H-SiC and SiO2: Microstructure, nanochemistry, and near-interface traps , 2005 .

[3]  V. Afanas’ev,et al.  Intrinsic SiC/SiO2 Interface States , 1997 .

[4]  Einar Ö. Sveinbjörnsson,et al.  On Shallow Interface States in n-Type 4H-SiC Metal-Oxide-Semiconductor Structures , 2002 .

[5]  L. Feldman,et al.  Effect of nitric oxide annealing on the interface trap densities near the band edges in the 4H polytype of silicon carbide , 2000 .

[6]  L. Feldman,et al.  Characterization and modeling of the nitrogen passivation of interface traps in SiO2/4H–SiC , 2003 .

[7]  M. Schulz,et al.  TRANSIENT CAPACITANCE MEASUREMENTS OF ELECTRONIC STATES AT THE SiO2-Si INTERFACE , 1978 .

[8]  Bo Monemar,et al.  Electron effective masses in 4H SiC , 1995 .

[9]  Tamara Rudenko,et al.  Interface trap properties of thermally oxidized n-type 4H–SiC and 6H–SiC , 2005 .

[10]  S. Dhar,et al.  Nitridation of the SiO2/4H–SiC interface studied by surface-enhanced Raman spectroscopy , 2007 .

[11]  A. Stoneham.  Theory of defects in solids , 1979 .

[12]  N. M. Johnson,et al.  Measurement of semiconductor–insulator interface states by constant‐capacitance deep‐level transient spectroscopy , 1982 .

[13]  Andre Stesmans,et al.  Mechanisms responsible for improvement of 4H-SiC/SiO2 interface properties by nitridation , 2003 .

[14]  Interface passivation for silicon dioxide layers on silicon carbide , 2005 .

[15]  P. Friedrichs,et al.  Significantly improved performance of MOSFETs on silicon carbide using the 15R-SiC polytype , 1999, IEEE Electron Device Letters.

[16]  Michael Bassler,et al.  “Carbon cluster model” for electronic states at interfaces , 1997 .

[17]  H. Matsunami,et al.  A cause for highly improved channel mobility of 4H-SiC metal–oxide–semiconductor field-effect transistors on the (112̄0) face , 2001 .

[18]  H. Card,et al.  Admittance measurements of Si‐SiO2 interface states under optical illumination , 1980 .

[19]  A. Stesmans,et al.  LETTER TO THE EDITOR: Photon-stimulated tunnelling of electrons in ?: evidence for a defect-assisted process , 1997 .