Semiconductor device having buried gate structure and method for manufacturing the same, memory cell having the same and electronic device having the same
A semiconductor device includes a substrate comprising a trench; a gate dielectric layer formed over a surface of the trench; a gate electrode positioned at a level lower than a top surface of the substrate, and comprising a lower buried portion embedded in a lower portion of the trench over the gate dielectric layer and an upper buried portion positioned over the lower buried portion; and a dielectric work function adjusting liner positioned between the lower buried portion and the gate dielectric layer; and a dipole formed between the dielectric work function adjusting liner and the gate dielectric layer.