A semiconductor device includes a substrate, a first transistor, and a second transistor. The first transistor includes a first source terminal formed of a material and connected to a first source, a first drain terminal formed of the material and connected to a first drain, a first gate overlapping a portion of the substrate that is between the first source and the first drain, and a first dielectric layer between the first gate and the substrate. The second transistor includes a control gate formed of the material and overlapping a part of the substrate that is positioned between a second source and a second drain, a second dielectric layer between the control gate and the substrate, a floating gate extending through the second dielectric layer to contact a doped region in the substrate, and an insulating member positioned between the control gate and the floating gate.