Semiconductor device having character in BPSG film

A semiconductor device comprising:

• a first BPSG film formed alone a semiconductor substrate and containing approximately 3.5 wt % to 4.5 wt % of boron and approximately 5.5 wt % to 6.5 wt % of phosphorus;
• and
• a second BPSG film formed on said first BPSG film and containing approximately 2.0 wt % to 3.0 wt % of boron and approximately 5.5 wt % to 6.5 wt % of phosphorus.

A semiconductor device comprising:

• a first BPSG film formed above a semiconductor substrate and containing approximately 3.5 wt % to 4.5 wt % of boron and phosphorus in a quantity slightly more than said boron;
• and
• a second BPSG film formed on said first BPSG film, in which the boron content is lower than that of said first BPSG film and the phosphorus content is almost equal to that of said first BPSG film.

A semiconductor device comprising:

• a first insulating film formed above a semiconductor substrate, said first insulating film containing approximately 3.5 wt % to 4.5 wt % of boron and approximately 5.5 wt % to 6.5 wt % of phosphorus and having a thickness of approximately 0.4 .mu.m to 1.0 .mu.m;
• and
• a second insulating film formed on said first insulating film, said second insulating film containing approximately 2.0 wt % to 3.0 wt % of boron and approximately 5.5 wt % to 6.5 wt % of phosphorus and having a thickness of approximately 0.05 .mu.m to 0.1 .mu.m.