Study of Silicon-Silicon Dioxide Structure by Electron Spin Resonance I

Three kinds of paramagnetic centers named P A, P B and P C have been found in a silicon-silicon dioxide structure at liquid nitrogen temperature. P A (g=∼2. 000, Δ H=∼4 Oe), and P B having anisotropic g-value (g=∼2. 000∼2. 010, Δ H=∼6 Oe) are in the exide, while P C which also has anisotropic g-value (g=∼2. 06∼2. 07, Δ H=∼9 Oe) is in the silicon near the Si-SiO 2 interface. Distribution of P B is successfully determined that it has the maximum concentration within about 400Å from the interface. P A and P B appear when the silicon is oxidized in dry oxidizing ambient or the Si-SiO 2 is cooled from elevated temperatures to room temperature with a cooling speed of about 500°C/sec. P C appears when the Si-SiO 2 is heated at elevated temperatures followed by rapid cooling to room temperature or is exposed to the ambient containing an appreciable amount of hydrogen at elevated temperatures such as 1000°C, for 10 min. P B is ascribed to a trivalent silicon -Si· which has a nonbonding orbital electron in the Si-O network. The mechanisms for the various behaviors of the centers are also discussed in detail.