A method for forming a semiconductor device with a single-sided buried strap is provided. The method includes the steps of providing a substrate with a trench, forming a semiconductor component in a lower portion of the trench to expose a higher portion of the trench, forming a first dielectric layer on a sidewall of the higher portion of the trench, forming a first conductive layer in the trench and adjacent to the first dielectric layer, forming a second dielectric layer on the first dielectric layer and the first conductive layer, forming a plurality of gate structures on the substrate, wherein one of the gate structures on the second dielectric layer is offset for a distance from the second dielectric layer, removing a portion of the second dielectric layer and a portion of the first dielectric layer to form an opening by using the gate structure as a mask, and forming a second conductive layer in the opening to electrically couple to the first conductive layer, whereby the semiconductor device with the single sided buried strap is formed.