Suppression of Boron Penetration in P⁺-Poly-Si Gate Metal-Oxide-Semiconductor Transistor Using Nitrogen Implantation

Abstract

The mechanism and the optimization of nitrogen implantation for suppression the boron penetration in p+-poly-Si gate metal-oxide-semiconductor capacitor is reported. This nitrogen co-implantation process exhibits a good suppression of boron penetration and a better electrical characteristic than that of control sample. It was found that nitrogen combines with the boron to form a B-N complex, retarding the penetration of boron itself, was identified by XPS measurements. The optimum nitrogen dosage is also found in this study.

The effect of fluorine from BF2 source/drain extension implants on performance of PMOS transistors with thin gate oxides

“…A range of methods was used to suppress fluorine enhanced boron penetration: nitrogen implantation into poly-Si [3], stacked amorphous/poly gate structure [4], and sacrificial gate stack process [5]. These techniques focus on preventing of fluorine migration from the implanted gate to the gate oxide.…”

A novel sacrificial gate stack process for suppression of boron penetration in p-MOSFET with shallow BF/sub 2/-implanted source/drain extension

“…Unfortunately, fluorine incorporation into the poly-Si gate is unavoidable as a result of BF implant that is often used to simultaneously dope the poly-Si gate and the S/D region. Previously, several methods have been proposed to alleviate the above-mentioned boron penetration problems, including the use of stacked amorphous/poly-Si p-type gate structure [4], [5], nitrogen co-implant into p poly-Si gate [6], and inductive-coupling-nitrogen-plasma process [7]. In this work, we propose a novel gate stack process to eliminate the incorporation of fluorine atoms into the p poly-Si gate while simultaneously preserving the advantage of using BF implant to form ultra-shallow S/D extension.…”

Suppression of cobalt silicide agglomeration using nitrogen (N/sub 2//sup +/) implantation

“…N ITROGEN implantation (N I/I) into the poly-Si gate has been proposed as a means of suppressing boron penetration through the thin gate oxide in surface-channel PMOSFET's [1], [2]. Although the N I/I is effective to suppress boron-penetration and the associated degradation of oxide reliability and hole mobility, and the shifts of threshold voltage, it will enhance the poly-depletion effect and increase gate resistance [2].…”