SRAM memory cell provided with transistors having a vertical multichannel structure

1. A microelectronic device comprising, on a substrate, at least one element comprising:

one or more first transistors including, in a direction forming a non-zero angle with the main plane of the substrate, a number n of parallel channels in a form of a plurality of bars parallel to each other and to the substrate, said bars being formed in a first stack comprising a first number of semiconductor layers and being aligned in a direction forming a non-zero angle with the main plane of the substrate; and

one or more second transistors including, in a direction forming a non-zero angle with the main plane of the substrate, a number m of parallel channels such that n>m in a form of a plurality of bars parallel to each other and to the substrate, said bars being formed in a second stack comprising a second number of semiconductor layers different from said first number of semi-conductor layers and being aligned in a direction forming a non-zero angle with the main plane of the substrate.

2. The microelectronic device according to claim 1 , wherein the element is a static random access memory cell, the cell comprising:

at least one access transistor and at least one other access transistor respectively including a number m of channels parallel in a direction forming a non-zero angle with the main plane of the substrate;

a plurality of transistors forming a flip-flop including at least one conduction transistor and at least one other conduction transistor respectively including a number n of channels parallel in a direction forming a non-zero angle, or an orthogonal direction, with the main plane of the substrate, n being greater than m.

3. A microelectronic device with a random access memory (RAM), comprising a plurality of cells according to claim 2 .

4. The microelectronic device according to claim 1 , wherein the element is a static random access memory cell, the cell comprising:

at least one access transistor and at least one other access transistor respectively including a number m of channels parallel in a direction forming a non-zero angle with the main plane of the substrate; and

a plurality of transistors forming a flip-flop, including at least one charge transistor and at least one other charge transistor respectively including a number k of channels parallel in a direction forming a non-zero angle, or an orthogonal direction, with the main plane of the substrate, m being greater than k.

5. The microelectronic device according to claim 1 , wherein the element is a logic gate or a logic circuit comprising one or more logic gates.

6. The microelectronic device according to claim 1 , the first transistor(s) being transistors of a first type between a P-type and an N-type,

the second transistor(s) being transistors of a second type, between a P-type and an N-type, and different from the first type.

7. A method to form a microelectronic device comprising:

forming on a substrate one or more elements, the forming comprising:

forming one or more first transistors respectively including, in a direction forming a non-zero angle with the main plane of the substrate, a number m of channels in a form of a plurality of bars parallel to each other and to the substrate; and

forming one or more second transistors respectively including, in a direction forming a non-zero angle with the main plane of the substrate, a number n of channels, such that n>m, in a form of a plurality of bars parallel to each other and to the substrate

wherein the m channels of the first transistor(s) are formed in a first stack comprising a first number of semiconductor layers, the n channels of the second transistor(s) being formed in a second stack comprising a second number of semiconductor layers different from the first number.

8. The method according to claim 7 , the first stack and the second stack being of a same height.

9. The method according to claim 8 , the second stack comprising semiconductor layers of different thickness.

10. The method according to claim 7 , the first stack and the second stack being formed of semiconductor layers in a first semiconductor material alternating with semiconductor layers in a second semiconductor material.

11. The method according to claim 7 , wherein the elements comprise cells of a SRAM memory.

12. The method according to claim 7 , wherein the elements comprise a logic gate or a logic circuit comprising one or more logic gates.

13. The method according to claim 12 , the first transistor(s) being transistors of a first type, between a P-type and an N-type, the second transistor(s) being transistors of a second type, between a P-type and an N-type, different from the first type.

14. A microelectronic device comprising, on a substrate, at least one element comprising:

one or more first transistors including, in a direction forming a non-zero angle with the main plane of the substrate, a number n of parallel channels in a form of a plurality of bars parallel to each other and to the substrate; and

one or more second transistors including, in a direction forming a non-zero angle with the main plane of the substrate, a number m of parallel channels such that n>m in a form of a plurality of bars parallel to each other and to the substrate,

wherein the element is a static random access memory cell, the cell including

at least one access transistor and at least one other access transistor respectively including a number m of channels parallel in a direction forming a non-zero angle with the main plane of the substrate, and

a plurality of transistors forming a flip-flop, including at least one charge transistor and at least one other charge transistor respectively including a number k of channels parallel in a direction forming a non-zero angle, or an orthogonal direction, with the main plane of the substrate, m being greater than k.