LARGE ANGLE TILT IMPLANT (LATI) METHOD FOR FORMING A LIGHTLY DOPED DRAIN (LDD)

摘要

LARGE ANGLE TILT IMPLANT (LATI) METHOD FOR FORMING A LIGHTLY DOPED DRAIN (LDD) A method for forming within a Metal Oxide Semiconductor Field Effect Transistor(MOSFET) a Lightly Doped Drain (LDD) low dose ion implant structure which partially overlapsa source/drain electrode high dose ion implant structure. To form the Lightly Doped Drain (LDD)low dose ion implant structure there is formed upon a semiconductor substrate a gate dielectric layerhaving formed thereupon a gate electrode. Formed then upon the exposed portions of thesemiconductor substrate, the gate dielectric layer and the gate electrode is an insulator layer. Finally;there is implanted through a Large Angle Tilt Implant (LATI) method a minimum of one low doseion implant through the insulator layer and into the semiconductor substrate to form the LightlyDoped Drain (LDD) low dose ion implant structure within the semiconductor substrate. The LightlyDoped Drain (LDD) low dose ion implant structure includes a portion of the semiconductor substratebeneath the gate electrode edges. As an extension of the method, there may additionally be implantedin-situ substantially orthogonally to the semiconductor substrate a minimum of one high dose ionimplant through the insulator layer and into the semiconductor substrate. The high dose ion implantis employed in forming a source/drain electrode high dose ion implant structure adjoining but notbeneath the gate electrode edges. As a further extension of the method, there may be formed apolysilicon layer upon the insulator layer. The polysilicon layer, if present, and/or the insulator layermay optionally be anisotropically etched to form a polysilicon spacer and/or an insulator spacer. Byforming the polysilicon layer prior to the low dose ion implant or the high dose ion implant, there isformed a low dose ion implant structure or a high dose ion implant structure with a shallower junctionwhich assists in reducing short channel effects.(FIGURE 2 IS SUGGESTED FOR PUBLICATION)