Formation of buried nitride silicon-on-insulator structures studied by Auger electron spectroscopy and transmission electron microscopy

The formation of buried nitride silicon-on-insulator structures is studied by means of Auger electron spectroscopy and transmission electron microscopy. 160-keV N+ ions are implanted to doses of 7.0 and 9.5×1017 atoms cm−2, respectively, at a substrate temperature of 550 °C. Annealing between 1150 and 1200 °C removes most of the damage in the top silicon layer in ≤ 1 h. In ≤ 13 h the buried layer turns into crystalline Si3N4. This crystallization process starts at a depth where the N concentration is well below the value for Si3N4.