MORPHOLOGY OF LPCVD SI3N4 FILMS AFTER HIGH-TEMPERATURE TREATMENT AND HF ETCHING

The influence of high temperature treatments in a nitrogen ambient at temperatures 1000 and 1100 degrees C and in water vapor at 900, 1000, and 1100 degrees C for 270 and 720 min on the structure, on the morpho logy and on the electrical properties of LPCVD Si3N4 layers has been i nvestigated. The Si3N4 layers have been deposited by the LPCVD techniq ue using the composition SiH2Cl2-NH3. The presence of a crystalline ph ase of alpha-Si3N4 has been established after 270 min annealing at 100 0 degrees C in water ambient. A sharp change of the surface morphology of the layers has been observed after wet etching in 40% HF for 10 s.