Characterization of PSG (Phosphosilicate Glass) Films Reflowed in Steam Using Rapid Thermal Processing

摘要

This study describes the use of a steam environment to reflow phosphosilicate glass (PSG) samples using a HEATPULSE rapid thermal annealer. The samples comprised PSG over poly steps and of open contacts in PSG. It was observed that reflow occurs 50 C lower in steam than in dry diatomic oxygen. An acceptable flow cycle for 8 w/o P PSG glass is 1050 c FOR 10 seconds in steam, while for 6 w/o P PSG it is 1100 C for 10 seconds. Steam is found to be an effective ambient for densification of the PSG film. The thermal oxide grown in the contact during opening reflow was determined to be near 140 A. The operating regime for a junction depth < or = micrometers and a reflow angle < or = 75 degs. is presented for 8 w/o phosphorus. (Reprints)