Abstract: An all-oxide transistor structure includes a substrate having an upper surface and a first transistor disposed on the upper surface of the substrate. The first transistor includes a first drain, a first dielectric layer, a first source, at least one first opening and a first channel layer. The first drain, the first dielectric layer and the first source are disposed on the substrate along a first direction, and the first direction is parallel to a normal direction of the upper surface. The first opening passes through the first drain, the first dielectric layer and the first source along the first direction. The first channel layer, the first gate dielectric layer and the first gate are disposed in the first opening. The first gate dielectric layer is disposed on the first channel layer. The first gate is disposed on the first gate dielectric layer.