A method of manufacturing a silicon layer includes pretreating a surface
of a silicon nitride layer formed on a substrate through a plasma
enhanced chemical vapor deposition method using a first reaction gas
including at least one of silicone tetrafluoride (SiF.sub.4) gas, a
nitrogen trifluoride (NF.sub.3) gas, SiF.sub.4--H.sub.2 gas and a mixture
thereof. Then, a silicon layer is formed on the pretreated silicon
nitride layer through the plasma enhanced chemical vapor deposition
method using a second reaction gas including a mixture of gas including
silicon tetrafluoride (SiF.sub.4), hydrogen (H.sub.2) and argon (Ar).