Enhanced flow of phosphosilicate glass by ion implantation

The phenomenon of enhanced flow of phosphosilicate glass (PSG) by ion implantation is reported here. By implanting As into PSG, excellent reflow has been obtained in inert ambients at temperatures as low as 750C. Sensitivity of reflow to percentage of oxygen (in nitrogen ambient) as well as to the energy of the As ions has been investigated. For the case of B, BF2, F, Ar, Se, and Sb implants, no similar reflow has been observed. CV and conduction experiments have shown the dielectric integrity to be unaffected by the implant. RBS depth profiling and resistivity measurements show As redistribution with no penetration to the substrate. This technology has been implemented into a VLSI process.