semiconductor substrate;

word lines extending in a first direction on the semiconductor substrate;

bit line structures extending across the word lines, the bit line structures extending in a second direction crossing the first direction;

contact pad structures between the word lines and between the bit line structures; and

spacers between the bit line structures and the contact pad structures, the spacers comprising a boron nitride layer comprising at least one of amorphous material and nanocrystalline material,

wherein

the bit line structures comprise a polysilicon pattern, a barrier/liner patter, a metal pattern, and a hard mask pattern, which are sequentially stacked on the semiconductor substrate, and

the spacers overlap the polysilicon pattern, the barrier/liner pattern, and the metal pattern with respect to the first direction.