Semiconductor device and method for fabricating the same, and memory system

Aspects of the disclosure provide a semiconductor device and a method to manufacture the semiconductor device. A channel hole is formed in a stack including alternating first layers and second layers. The stack is formed over a substrate of the semiconductor device. A gate dielectric layer and a channel layer are sequentially formed in the channel hole. Laser annealing is performed on the channel layer using laser light. An incidence angle of the laser light on an upper surface of the channel layer causes a total internal reflection to occur at an interface between the channel layer and the gate dielectric layer and an interface between the channel layer and an insulating layer that is adjacent to the channel layer.