Electrical characterization of the SiON/Si interface for applications on optical and MOS devices

An investigation of the electrical properties of the SiON/n-Si interface is presented for applications in MOS and/or optical devices. The SiON films were deposited onto n-type Si substrates by CVD using different [O]/[N] ratios. Subsequent metallization led to the creation of metal-oxide-semiconductor (MOS) devices and electrical characterization took place in order to identify their electrical properties. Electrical measurements included current–voltage, capacitance–conductance–voltage ( C – G – V ) measurements and admittance spectroscopy, allowing the determination of the interface state density, the traps time constant and their distribution. Post-deposition annealing was also used and the annealed samples were subjected to the same investigation. The interface state density was found to lie between 1.74 × 10 12 eV −1 cm 2 and 1.72 × 10 11 eV −1 cm −2 and the post-deposition annealing reduced these values.