Electrical Properties of Silicon Oxide Layers Subjected to High-Temperature Treatment Reproducing the Growth Conditions for Thin Carbon Films

The extraordinary behavior of the oxide charge in SiO 2 /Si structures processed under the conditions reproducing chemical-vapor-deposition (CVD) growth of thin carbon films is reported. The charge in the SiO 2 dielectric layers and the SiO 2 /Si interface quality in the structures subjected to high-temperature annealing in a CVD reactor were studied using a high-frequency capacitance–voltage technique. It is shown that a huge positive charge is generated in the SiO 2 dielectric layers under annealing in an ethanol-containing atmosphere at temperatures of about 600–700°C. The surface density of the induced oxide charge can be as high as 4 × 10 12 cm −2 and is expected to strongly influence the parameters and performance of fabricated metal–oxide–semiconductor devices. The positive charge induced in the SiO 2 layers is presumably related to carbon diffusion which starts to be effective at 600–700°C. The quality of the SiO 2 /Si interface significantly degraded after annealing at temperatures higher than 700°C, however, no explicit relationship to a precursor used for CVD growth was found.