RTP ANNEALINGS FOR HIGH-QUALITY LPCVD INTERPOLYSILICON DIELECTRIC LAYERS

Deposited instead of thermally grown oxides were studied to form high- quality interpolysilicon dielectric layers for embedded non-volatile m emory application. It was found that by optimizing the texture and mor phology of the polysilicon layers and by optimizing the post-dielectri c deposition-anneal, very high-quality dielectric layers can be obtain ed. In this paper it is shown that for deposited interpolysilicon oxid es rapid thermal annealing leads to improved electrical characteristic s, like high charge to breakdown (Q(bd)approximate to 20 C/cm(2)), low er leakage currents and decreased charge trapping during stress, depen ding on the RTP anneal ambient. Three annealing ambients are compared: N-2, O-2 and N2O. Annealing in N2O ambient is shown to be superior to the other annealings. (C) 1998 Elsevier Science Ltd.