| 摘要 |
PURPOSE: A method for fabricating a nonvolatile semiconductor memory device is provided to prevent degradation in an isolation property of a field oxide layer. CONSTITUTION: In the method, the field oxide layer(11) is selectively formed on a silicon substrate(10), and a tunneling oxide layer(13) is grown in an active region. A polysilicon layer for a floating gate(20) is then formed thereon and removed along top portions of the field oxide layer(11). A dielectric layer(30) is then formed on an entire surface and covered with a lower polysilicon layer and an upper tungsten silicide layer for forming a control gate. Thereafter, when the control gate is patterned, remainders of the lower polysilicon layer form spacers(45) on confronting sides of the adjacent floating gates(20). The dielectric layer(30) is then etched by using the spacers(45) as a mask until the field oxide layer(11) is exposed between the floating gate(20) and the spacer(45). Here, the field oxide layer(11) exposed between the spacers(45) is also etched to form a groove(112). Thereafter, the remaining floating gate(20) is totally removed together with the spacers(45) except the dielectric layer(30) lying under the spacers(45). The groove(112) is then filled with an oxide layer for enhancing the isolation property.
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