Abstract: Lightly Doped Drain (LDD) MOSFET developed from the conventional MOSFET, is a new structure for MOS devices. Some short channel effects including the hot electron effect in this new structure can be restrained effectively. In this paper a comparison between overcut etching and side wall technology for LDD MOSFET is given. It shows that the side wall technology is a more precise one to control the length of the lightly doped drain region. Combining the side wall technology with the Si-gate NMOS technology, the LDD MOSFET with 1 micrometer channel length is made successfully. The results of test show that the breakdown voltage of LDD MOSFET is higher than that of the conventional MOSFET over 3 volts and the short channel effects of the threshold voltage are restrained obviously. The LDD MOSFET is a suitable structure for VLSI.

Key words: side wall technology, LDD MOSPET (Lightly Doped Drain Metal-Oxide-Semiconductor Field Effect Transistor), short channel effect