Architecture with stacked N and P transistors with a channel structure formed of nanowires
A device with stacked transistors includes a first transistor of a first type, in particular N or P, the first transistor having a channel formed in one or more first semi-conducting rods of a semi-conducting structure including semi-conducting rods disposed above each other and aligned with each other, and a second transistor of a second type, in particular P or N, with a gate-surrounding gate and a channel region formed in one or more second semi-conducting rods of said semi-conducting structure and disposed above the first semi-conducting rods. The source block of the second transistor is distinct from the source and drain block of the second transistor, and the drain block of the second transistor is distinct from the drain and source blocks of the second transistor.
1. A device with stacked transistors comprising:
a first transistor of a first conductivity type, the first transistor having a channel formed in one or more first semi-conducting rods of a semi-conducting structure including semi-conducting rods disposed above each other, extending in a longitudinal direction, and aligned with each other, a first source or drain block of the first transistor and a second drain or source block of the first transistor being disposed at first ends of the one or more first semi-conducting rods, the first transistor being provided with a first gate,
a second transistor of a second conductivity type, having a channel region formed in one or more second semi-conducting rods of said semi-conducting structure disposed above each other and extending in the longitudinal direction, the second semi-conducting rods being disposed above the first semi-conducting rods, a third drain or source block of the second transistor and a fourth drain or source block being respectively disposed at second ends of the one or more second semi-conducting rods, the second transistor being provided with a second gate,
the third source or drain block of the second transistor being formed above and being distinct from the first source or drain block of the second transistor, the fourth drain or source block of the second transistor being disposed above and being distinct from the second drain or source block of the second transistor,
a first conducting element in contact with the first block and passing through the third block while being insulated from the third block,
a second conducting element in contact with said second block and passing through the fourth block while being insulated from the fourth block,
a third conducting element in contact with said third block, and
a fourth conducting element in contact with said fourth block,
the first conducting element and the second conducting element being distinct and electrically insulated from said third conducting element and from said fourth conducting element, wherein
the first and second gates of the first and second transistors are electrically isolated from each other,
the first and second semi-conducting rods each have respective first and second lateral faces opposing each other in a lateral direction orthogonal to the longitudinal direction,
the first gate of the first transistor is a partially surrounding gate covering upper and lower faces and first lateral faces of one or more of the first semi-conducting rods without covering second lateral faces of the first semi-conducting rods,
the second gate of the second transistor is a partially surrounding gate covering upper and lower faces and second lateral faces of one or more of the second semi-conducting rods without covering first lateral faces of the second semi-conducting rods,
the first gate of the first transistor includes a first vertical portion extending facing the first lateral face of the first rods and the second rods,
an insulating zone is arranged between a region of the first vertical portion and the first lateral face of said second rods, and
the second gate of the second transistor includes a second vertical portion extending facing the second lateral face of the second semi-conducting rods.
2. The device according to claim 1 , wherein the first conducting element, the second conducting element, the third conducting element, the fourth conducting element each have a first end located above the semi-conducting structure, and a second end in contact with a source or drain block, the first conducting element, the second conducting element, the third conducting element, the fourth conducting element each extending between the first end and the second end along a main axis of extension without changing direction along this main axis of extension.
3. The device according to claim 1 , wherein
the first transistor and the second transistor are arranged on a substrate having a horizontal main plane,
the first conducting element is formed by a vertical conducting portion having an end in contact with the first block,
the second conducting element is formed by a vertical conducting portion having an end in contact with said second block,
the third conducting element is formed by a vertical conducting portion having an end in contact with said third block, and
the fourth conducting element is formed by a vertical conducting portion having an end in contact with said fourth block.
4. The device according to claim 1 , wherein the first conducting element is in contact with the first block, said first conducting element being insulated from the third block through an insulating sheath surrounding said first conducting element, the second conducting element being in contact with said second block, said second conducting element being surrounded by another insulating sheath, and said second conducting element being insulated from said fourth block through said other insulating sheath.
5. The device according to claim 1 , wherein the first gate of the first transistor is a surrounding gate arranged around said one or more first rods, and wherein the second gate of the second transistor is a surrounding gate arranged around said one or more second rods.
6. The device according to claim 1 , wherein the first conductivity type is N, and the second conductivity type is P.
7. The device according to claim 1 , wherein the first conductivity type is P, and the second conductivity type is N.
8. The device according to claim 1 , wherein
the first gate of the first transistor comprises a first surrounding portion arranged around said one or more first rods and a first lead portion extending from the first surrounding portion to above the one or more second rods,
the second gate of the second transistor comprises a second surrounding portion arranged around said one or more second rods and a second lead portion extending from the second surrounding portion to above the one or more second rods, and
the first and second lead portions are arranged on opposing sides of the one or more second rods.
9. The device according to claim 8 , comprising a separation portion disposed between the first and second transistors, the separation portion comprising a stacked structure comprising a part of the first surrounding portion of the first gate of the first transistor and a part of the second surrounding portion of the second gate of the second transistor separated by at least one layer.
10. The device according to claim 1 , wherein the first conducting element passes through the third block without passing through the second gate of the second transistor, said second conducting element passing through said fourth block without passing through the second gate of the second transistor.
11. A method for making a device according to claim 5 , comprising:
forming said first block and said second block of the first transistor,
forming said third block and said fourth block of the second transistor, and then steps of:
forming holes through the third block and the fourth block of the second transistor, the holes revealing the first block and the second block respectively,
forming an insulating sheath on vertical walls of the holes, and then
depositing conducting material into the holes.
12. The method according to claim 11 , wherein, after forming the insulating sheath and prior to filling the holes with said conducting material, the method comprises steps of:
plugging the holes with a given material,
making second holes revealing the third block and the fourth block of the second transistor respectively, and
removing said given material, the deposition of said conducting material being then performed into said holes and said second holes.