Ribbon or wire transistor stack with selective dipole threshold voltage shifter

A computer system, comprising:

• a power supply;
• and
• an IC die coupled to the power supply, the IC die comprising an integrated circuit (IC) structure comprising a CMOS transistor stack, wherein the CMOS transistor stack comprises:
• a first channel region of a first conductivity type over a second channel region of a second conductivity type, complementary to the first, wherein the first and the second channel regions comprise at least one of Si or Ge;
• a gate electrode around the first channel region, and around the second channel region;
• a first gate insulator material between the gate electrode and each of the first channel region and the second channel region, wherein the first gate insulator material comprises oxygen and a first metal and encircles each of the first channel region and the second channel region;
• a second gate insulator material in direct contact with the first channel region, and between the first channel region and the first gate insulator material encircling the first channel region;
• and
• a third gate insulator material in direct contact with the second channel region, and between the second channel region and the first gate insulator material encircling the second channel region, wherein:
• both of the second and the third gate insulator materials comprise oxygen and the at least one of Si or Ge;
• at least one of the second and third gate insulator materials comprise a second metal;
• and
• an amount of the second metal varies between the second and third gate insulator materials.

A transistor stack structure, comprising:

• a first channel region over a second channel region, wherein the first and the second channel regions comprise at least one of Si or Ge;
• a gate electrode around the first channel region, and around the second channel region;
• a first source material coupled to a first drain material through the first channel region, wherein the first source material and the first drain material are of a first conductivity type;
• a second source material coupled to a second drain material through the second channel region, wherein the second source material and the second drain material are of a second conductivity type, complementary to the first conductivity type;
• a first gate insulator material between the gate electrode and each of the first channel region and the second channel region, wherein the first gate insulator material comprises oxygen and a first metal and encircles each of the first channel region and the second channel region;
• a second gate insulator material in direct contact with the first channel region, and between the first channel region and the first gate insulator material encircling the first channel region, and in direct contact with the first channel region;
• and
• a third gate insulator material in direct contact with the second channel region, between the second channel region and the first gate insulator material encircling the second channel region, wherein:
• both of the second and the third gate insulator materials comprise oxygen and the at least one of Si or Ge;
• at least one of the second and third gate insulator materials comprise a second metal;
• and
• the second metal is Al, Ga, Mo, Co, Ni, or Nb and an amount of the second metal is greater in the second gate insulator material than in the third gate insulator where the first conductivity type is P-type, and the amount of the second metal is greater in the third gate insulator material than in the second gate insulator material where the first conductivity type is N-type, or the second metal is Mg, Ca, Sr, Ba, La, Sc, Y, Gd, Er, Yb, or Lu, and an amount of the second metal is greater in the second gate insulator material than in the third gate insulator where the first conductivity type is N-type, and the amount of the second metal is greater in the third gate insulator material than in the second gate insulator material where the first conductivity type is P-type.