Method for producing a semiconductor gate conductor having an impurity migration barrier

A method for reducing diffusion of boron dopant from a patterned semiconductor gate conductor to an underlying n- type channel region, the method comprising:

• providing a semiconductor n- type substrate and a first layer of dielectric material across one surface of the substrate;
• providing a conductive material across the dielectric material, said conductive material having an upper and lower surface wherein the upper surface is exposed and the lower surface is adjacent the dielectric material;
• implanting germanium into the conductive material via the exposed surface to a concentration peak density at a first depth relative to the upper surface of said conductive material, said first depth is substantially equal to 1030 .ANG.;
• selectively removing a portion of the conductive material and underlying dielectric material to present a source region, a drain region and a patterned gate conductor having a thickness substantially equal to said conductive material, said source and drain regions are spaced apart within said substrate by a channel region underlying the patterned gate conductor;
• implanting ionized BF.sub.2 into the source and drain regions simultaneous with implanting ionized BF.sub.2 into the patterned gate conductor to a concentration peak density at a second depth within said gate conductor relative to the initial upper surface of said conductive material, said second depth is substantially equal to 500 .ANG.;
• applying metal to said patterned gate conductor and said source and drain regions;
• depositing in liquid form a second layer of dielectric material across the metal and the patterned gate conductor;
• and
• curing the second layer of dielectric material at a temperature sufficient to simultaneously anneal the patterned gate conductor and the source and drain regions.

A method for producing a boron dopant diffusion barrier in a semiconductor gate conductor, the method comprising the steps of:

• providing a semiconductor substrate and a first layer of dielectric material onto said substrate and a conductive material onto said dielectric material;
• implanting germanium ions diffusion barrier into said conductive material to a concentration peak density at a first depth;
• selectively removing a portion of the conductive material and underlying dielectric material to present a patterned gate conductor spaced above said substrate and a source region and a drain region within said substrate, said source and drain regions are spaced apart within said substrate by a channel regions underlying the patterned gate conductor;
• implanting BF.sub.2 dopant ions into the source and drain regions simultaneous with implanting BF.sub.2 dopant ions into the patterned gate conductor to a concentration peak density at a second depth, wherein said second depth is shallower than said first depth;
• and
• heating the substrate at a temperature sufficient to anneal the patterned gate conductor, whereby a barrier is formed by said germanium ions and the barrier remains between at least 80% of said BF.sub.2 ions within said patterned gate conductor and said channel region.