An integrated circuit includes a first semiconductor device and a second semiconductor device adjacent to the first semiconductor device. Each of the first and second semiconductor devices includes a lower transistor and an upper transistor on the lower transistor, and the upper and lower transistors each include a source region, a drain region, and a channel region extending between the source region and the drain region. The integrated circuit also includes a first dielectric spacer extending along an inner sidewall of the channel region of the upper and/or lower transistor of the first semiconductor device, a second dielectric spacer facing the first dielectric spacer and extending along an inner sidewall of the channel region of the upper and/or lower transistor of the second semiconductor device. The integrated circuit also includes an interconnect contact between the first semiconductor device and the second semiconductor device.