Semiconductor device and method
A method includes forming first devices in a first region of a substrate, wherein each first device has a first number of fins; forming second devices in a second region of the substrate that is different from the first region, wherein each second device has a second number of fins that is different from the first number of fins; forming first recesses in the fins of the first devices, wherein the first recesses have a first depth; after forming the first recesses, forming second recesses in the fins of the second devices, wherein the second recesses have a second depth different from the first depth; growing a first epitaxial source/drain region in the first recesses; and growing a second epitaxial source/drain region in the second recess.
1 . A method comprising:
forming first devices in a first region of a substrate, wherein each first device has a first number of fins;
forming second devices in a second region of the substrate that is different from the first region, wherein each second device has a second number of fins that is different from the first number of fins, wherein the fins of the first devices are separated from the fins of the second devices;
forming first spacers on the fins of the first devices and second spacers on the fins of the second devices, wherein the first spacers extend farther from the substrate than the second spacers;
after forming the first spacers and the second spacers, forming first recesses in the fins of the first devices, wherein the first recesses have a first depth;
after forming the first recesses, forming second recesses in the fins of the second devices, wherein the second recesses have a second depth different from the first depth;
growing a first epitaxial source/drain region in the first recesses; and
growing a second epitaxial source/drain region in the second recesses, wherein the first epitaxial source/drain region and the second epitaxial source/drain region have a same doping type.
2 . The method of claim 1 , wherein the first number is less than the second number.
3 . The method of claim 2 , wherein the first number is one.
4 . The method of claim 1 , wherein each second device has four or more fins.
5 . The method of claim 1 , wherein the second depth is greater than the first depth.
6 . The method of claim 5 , wherein the second depth is between 5 nm and 20 nm greater than the first depth.
7 . The method of claim 1 , wherein forming the first recesses comprises performing a first etching process and forming the second recesses comprises performing a second etching process that is different than the first etching process.
8 . The method of claim 1 , wherein the second epitaxial source/drain region is larger than the first epitaxial source/drain region.
9 . The method of claim 1 , wherein forming the second recesses reduces a height of the second spacers.
10 . A method comprising:
forming a first semiconductor device in a substrate, the forming of the first semiconductor device comprising:
forming a fin protruding from the substrate;
forming a first gate stack extending over the fin;
forming a first recess in the fin adjacent the first gate stack, wherein the first recess in the fin has a first depth; and
forming a first epitaxial source/drain region in the first recess;
forming a second semiconductor device in the substrate, the forming of the second semiconductor device comprising:
forming two adjacent fins protruding from the substrate;
forming a second gate stack extending over the two adjacent fins;
forming a second recess in each of the two adjacent fins adjacent the second gate stack, wherein the second recess in each of the two adjacent fins has a second depth that is greater than the first depth; and
forming a second epitaxial source/drain region in each second recess; and
forming a third semiconductor device in the substrate comprising:
forming three adjacent fins protruding from the substrate;
forming a third gate stack extending over the three adjacent fins;
forming a third recess in each of the three adjacent fins adjacent the third gate stack, wherein the third recess in each of the three adjacent fins has a third depth that is greater than the second depth; and
forming a third epitaxial source/drain region in each third recess.
11 . The method of claim 10 , wherein the third depth is between 7 nm and 27 nm greater than the first depth.
12 . The method of claim 10 , wherein the second depth is between 5 nm and 20 nm greater than the first depth.
13 . The method of claim 10 , wherein the first semiconductor device comprises first spacers on the first gate stack, and the second semiconductor device comprises second spacers on the second gate stack, wherein the first spacers have a first height above the substrate that is greater than a second height above the substrate of the second spacers.
14 . A method comprising:
forming a first device in a first region of a substrate, wherein the first device has a first number of fins;
forming a second device in a second region of the substrate that is different from the first region, wherein the second device has a second number of fins, wherein the second number is different from the first number, wherein the fins of the first device are separated from the fins of the second device, wherein the fins of the first device and the fins of the second device have a same pitch;
forming first spacers on the fins of the first device and forming second spacers on the fins of the second device, wherein the first spacers extend farther from the substrate than the second spacers;
after forming the first spacers and the second spacers, forming first recesses in the fins of the first device, wherein the first recesses are formed to have a first depth;
after forming the first recesses, forming second recesses in the fins of the second device, wherein the second recesses are formed to have a second depth different from the first depth;
growing a first epitaxial source/drain region in the first recesses; and
growing a second epitaxial source/drain region in the second recesses, wherein the first epitaxial source/drain region and the second epitaxial source/drain region have a same doping type.
15 . The method of claim 14 , wherein the second number is larger than the first number, and the second depth is greater than the first depth.
16 . The method of claim 14 , wherein the first recesses are formed by etching the fins of the first device using a first etching process, wherein the second recesses are formed by etching the fins of the second device using a second etching process that is different from the first etching process.
17 . The method of claim 14 , wherein the fins of the first device are formed on a first raised portion of the substrate, and the fins of the second device are formed on a second raised portion of the substrate, wherein the second raised portion is wider than the first raised portion.
18 . The method of claim 17 , further comprising forming isolation regions along the fins of the first device and along the fins of the second device, wherein the isolation regions comprise:
a first isolation region between the first raised portion and the second raised portion; and
a second isolation region between the fins of the second device, wherein a lower surface of the second isolation region facing the substrate extends farther from the substrate than a lower surface of the first isolation region facing the substrate.
19 . The method of claim 17 , wherein at least one of the fins of the first device has a sidewall that is flush with a sidewall of the first raised portion, wherein at least one of the fins of the second device has a sidewall that is flush with a sidewall of the second raised portion.
20 . The method of claim 14 , wherein forming the first recesses reduces a height of the first spacers, wherein forming the second recesses reduces a height of the second spacers.