Semiconductor devices with graded dopant regions

A VLSI semiconductor device, comprising:

• a substrate of a first doping type at a first doping level having a surface;
• a first active region disposed adjacent the surface of the substrate with a second doping type opposite in conductivity to the first doping type and within which transistors can be formed in the surface thereof;
• a second active region separate from the first active region disposed adjacent to the first active region and within which transistors can be formed in the surface thereof;
• transistors formed in at least one of the first active region or second active region;
• at least a portion of at least one of the first and second active regions having at least one graded dopant concentration to aid carrier movement from the surface to an area of the substrate where there are no active regions;
• and
• at least one well region adjacent to the first or second active region containing at least one graded dopant region, the graded dopant region to aid carrier movement from the surface to the area of the substrate where there are no active regions, and wherein the graded dopant concentration is linear, quasilinear, error function, complementary error function, or any combination thereof.

A semiconductor device, comprising:

• a substrate of a first doping type at a first doping level;
• a first active region disposed adjacent to a surface of the substrate with a second doping type opposite in conductivity to the first doping type and within which transistors can be formed;
• a second active region separate from the first active region disposed adjacent to the first active region and within which transistors can be formed;
• transistors formed in at least one of the first active region or second active region;
• and
• at least a portion of at least one of the first and second active regions having at least one graded dopant concentration to aid carrier movement from the first or second active region to at least one substrate area where there is no active region.

A semiconductor device, comprising:

• a substrate of a first doping type at a first doping level;
• a first active region disposed adjacent to a surface of the substrate with a second doping type opposite in conductivity to the first doping type and within which transistors can be formed;
• a second active region separate from the first active region disposed adjacent to the first active region and within which transistors can be formed;
• transistors formed in at least one of the first active region or second active region;
• and
• at least a portion of at least one of the first and second active regions having at least one graded dopant acceptor concentration to aid carrier movement from the first or second active region to at least one substrate area where there is no active region.

A semiconductor device, comprising:

• a substrate of a first doping type at a first doping level;
• a first active region disposed adjacent to a surface of the substrate with a second doping type opposite in conductivity to the first doping type and within which transistors can be formed;
• a second active region separate from the first active region disposed adjacent to the first active region and within which transistors can be formed;
• transistors formed in at least one of the first active region or second active region;
• and
• at least a portion of at least one of the first and second active regions having at least one graded donor dopant concentration to aid carrier movement from the first or second active region to at least one substrate area where there is no active region.

A semiconductor device, comprising:

• a substrate of a first doping type at a first doping level;
• a first active region disposed adjacent to a surface of the substrate with a second doping type opposite in conductivity to the first doping type and within which transistors can be formed;
• a second active region separate from the first active region disposed adjacent to the first active region and within which transistors can be formed;
• transistors formed in at least one of the first active region or second active region;
• and
• at least a portion of at least one of the first and second active regions having at least one graded acceptor dopant concentration and one graded donor dopant concentration to aid carrier movement from the first or second active region to at least one substrate area where there is no active region.

A CMOS Semiconductor device comprising:

• a surface layer;
• a substrate;
• an active region including a source and a drain, disposed on one surface of the surface layer;
• a single drift layer disposed between the other surface of the surface layer and the substrate, the drift layer having a graded concentration of dopants extending between the surface layer and the substrate, the drift layer further having a first static unidirectional electric drift field to aid the movement of carriers from the surface layer to an area of the substrate where there are no active regions;
• and
• at least one well region disposed in the single drift layer, the well region having a graded concentration of dopants and a second static unidirectional electric drift field to aid the movement of carriers from the surface layer to the area of the substrate where there are no active regions.