Transistors and memory arrays

Some embodiments include a transistor having a semiconductor material with a trench extending downwardly therein. The semiconductor material has a first post region on one side of the trench and a second post region on an opposing side of the trench. The semiconductor material has a narrow fin region along the bottom of the trench and extending between the first and second post regions. Each of the first and second post regions has a first thickness and the narrow fin region has a second thickness, with the second thickness being less than the first thickness. Gate dielectric material is along sidewalls of the first and second post regions, along a top of the narrow fin region, and along side surfaces of the narrow fin region. Gate material is over the gate dielectric material. First and second source/drain regions are within the first and second post regions.