Drive current enhancement by ideal junction profile using laser thermal process

Yamamoto, Tsuyoshi; Goto, Ken; Tada, Yutaka; Kikuchi, Y.; Kubo, T.; Wang, Y.; Talwar, S.; Kase, M.; Sugii, T.

doi:10.1109/vlsit.2002.1015426

Cited by 5 publications

(6 citation statements)

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“…Therefore, the adjustment of melt depth is a key to controlling the junction depth (X j ) with melt-type LA. Laser thermal processing (LTP) is one of the most famous approaches for coping with this problem [5], [9]. LTP utilizes melting of an amorphous-silicon (a-Si) layer that was formed by Ge + or Si + preamorphization implantation (PAI).…”

Section: Introductionmentioning

confidence: 99%

Merits of heat assist for melt laser annealing

Shibahara

Eto

Kurobe

2006

IEEE Trans. Electron Devices

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In this paper, the potential for sub-10-nm junction formation of partial-melt laser annealing (PMLA), which is a combination of solid-phase regrowth and heat-assisted laser annealing (HALA), is demonstrated. HALA and PMLA are effective for reducing laser-energy density for dopant activation and for improving heating uniformity of device structure. The absence of melting at the dopant profile tail for PMLA results in a negligibly small diffusion at this region. A high activation rate is achievable by melting the upper part of the amorphous-silicon layer. The obtained sheet resistance of 10-nm-deep junctions was about 700 Ω/sq. for both n + /p and p + /n junctions. These results imply that PMLA is applicable for much shallower junction formation.

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Section: Introductionmentioning

confidence: 99%

Merits of heat assist for melt laser annealing

Shibahara

Eto

Kurobe

2006

IEEE Trans. Electron Devices

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“…In order to continue scaling down the size of metaloxide-semiconductor field-effect transistors (MOSFETs), low-resistive ultrashallow source and drain extensions (SDE) are required to improve MOSFET performance and to prevent the undesirable influences of short-channel effects and parasitic resistance. 1) Moreover, accurate control of a dopant profile at a junction is expected, because handling unwanted diffusion is critical to designing MOSFETs because of the short-channel effects. It is difficult to maintain dopant profiles formed by ion implantation, since transient enhanced diffusion causes undesirable spreading of the junction depth (X j ).…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, high-temperature, short-time annealing is desired to obtain ultrashallow junctions with sufficiently low sheet resistance (R s ). Flash lamp annealing 4) and laser annealing (LA) 1) have been proposed as possible alternative methods for high-temperature, short-time annealing to replace conventional rapid thermal annealing (RTA). The KrF excimer laser offers some special advantages, such as ultrashallow penetration depth in Si (5.5 nm) due to its relatively short wavelength (248 nm) and short pulse duration (on the order of nanoseconds) compared with other lasers.…”

Section: Introductionmentioning

confidence: 99%

Sheet Resistance Reduction and Crystallinity Improvement in Ultrashallow n⁺/p Junctions by Heat-Assisted Excimer Laser Annealing

Kurobe

Ishikawa

Shibahara

2005

Jpn. J. Appl. Phys.

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Low-resistive ultrashallow n+/p junctions were formed with Sb as a dopant by heat-assisted laser annealing. A process window platted against laser energy density and substrate temperature was obtained in which the sheet resistance was about 500 Ω/sq. while the junction depth was maintained at about 20 nm, which was equal to that of the as implanted condition. Cross-sectional transmission electron microscopy (XTEM) images showed that substrate heating before laser irradiation enhanced recrystallization of the amorphized layer. This causes non melt laser annealing using the complete recrystallization of the amorphized layer. From current–voltage characteristics of n+/p diodes in the reverse direction, leakage current reduction accompanying the heat-assisted annealing was confirmed.

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“…3,4) In addition, dopant profiles can be finely controlled by controlling the preamorphization depth that is formed by heavy ion implantation. 5) This is based on the fact that the melting to recrystallization can be induced selectively in the amorphous Si by laser annealing under appropriate laser-power conditions because amorphous Si melts at a temperature lower than that needed to melt single-crystal Si. Thus, this technique, which enables selective melting and activation of the dopant at a relatively lower laser power, is advantageous to CMOS process integration.…”

Section: Introductionmentioning

confidence: 99%

Realization of Low CoSi₂/p⁺-Silicon Contact Resistance with Low Junction Leakage Current and Junction Capacitance Using Laser Thermal Process

Yamamoto

Kubo

Wang³

et al. 2005

Jpn. J. Appl. Phys.

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In this paper we report source–drain engineering for the realization of low contact resistance between CoSi2 and p+ Si with low junction leakage current and low junction capacitance using laser thermal processing (LTP) and the optimization of ion implantation conditions. We first demonstrate the impact of pre-amorphization on the reduction of the contact resistivity of a CoSi2/p+ deep source–drain (deep-SD) interface using laser thermal processing (LTP). A highly activated dopant profile at the CoSi2/deep-SD interface is required to reduce the contact resistivity there. Dopant profile can be finely controlled by implanting heavy ions to preamorphize a region to the desired depth and then using an appropriate laser power to selectively melt the amorphous Si, which has a melting temperature lower than that of single-crystal Si. We can thus form a highly activated boxlike dopant profile suitable for a deep-SD by using LTP and relatively deep preamorphization. Then, we discuss how to suppress the leakage current and the capacitance of the junctions. The larger junction capacitance and junction leakage current due to the abrupt deep-SD profile can be greatly reduced by combining LTP with lower-dose, higher-energy implantation and RTA prior to preamorphization (predoping and pre-RTA) to form a graded deep-SD profile beyond the abrupt deep-SD profile and overwhelm the channel doping profile, resulting in a wide depletion layer.

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Drive current enhancement by ideal junction profile using laser thermal process

Cited by 5 publications

References 0 publications

Merits of heat assist for melt laser annealing

Merits of heat assist for melt laser annealing

Sheet Resistance Reduction and Crystallinity Improvement in Ultrashallow n⁺/p Junctions by Heat-Assisted Excimer Laser Annealing

Realization of Low CoSi₂/p⁺-Silicon Contact Resistance with Low Junction Leakage Current and Junction Capacitance Using Laser Thermal Process

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Drive current enhancement by ideal junction profile using laser thermal process

Cited by 5 publications

References 0 publications

Merits of heat assist for melt laser annealing

Merits of heat assist for melt laser annealing

Sheet Resistance Reduction and Crystallinity Improvement in Ultrashallow n+/p Junctions by Heat-Assisted Excimer Laser Annealing

Realization of Low CoSi2/p+-Silicon Contact Resistance with Low Junction Leakage Current and Junction Capacitance Using Laser Thermal Process

Contact Info

Product

Resources

About

Sheet Resistance Reduction and Crystallinity Improvement in Ultrashallow n⁺/p Junctions by Heat-Assisted Excimer Laser Annealing

Realization of Low CoSi₂/p⁺-Silicon Contact Resistance with Low Junction Leakage Current and Junction Capacitance Using Laser Thermal Process