Salicides for 0.10 /spl mu/m gate lengths: a comparative study of one-step RTP Ti with Mo doping, Ti with pre-amorphization and Co process

Kittl,; Hong, Qi-Zhong; Chao, Calvin Yi‐Ping; Chen, Ih-Chin; Yu, Ning; O'Brien, Vincent; Hanratty,

doi:10.1109/vlsit.1997.623716

Cited by 13 publications

(6 citation statements)

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“…7 In addition, the high temperatures required to transform C49 TiSi 2 to C54 TiSi 2 on deep-submicron structures, can result in agglomera-tion and degradation of device contact resistance and drive current. 1,2, [9][10][11] An alternative approach, the addition of Mo impurities close to the Ti/Si interface, was shown to result in easier formation of C54 TiSi 2 on submicron structures. 6,8,10,11 In situ x-ray diffraction ͑XRD͒ studies showed that the temperature of the C49 to C54 transformation was reduced for the reaction of Ti with Mo doped single crystal ͑100͒ Si.…”

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confidence: 99%

“…1,2, [9][10][11] An alternative approach, the addition of Mo impurities close to the Ti/Si interface, was shown to result in easier formation of C54 TiSi 2 on submicron structures. 6,8,10,11 In situ x-ray diffraction ͑XRD͒ studies showed that the temperature of the C49 to C54 transformation was reduced for the reaction of Ti with Mo doped single crystal ͑100͒ Si. 6 Extension of Ti salicide with low sheet resistance to 0.10 m features using Mo impurities 10 and to 0.06 m using Mo impurities and PAI 11 was demonstrated, for low temperature single RTP step processes, with excellent contact resistance and drive currents.…”

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confidence: 99%

“…6 Extension of Ti salicide with low sheet resistance to 0.10 m features using Mo impurities 10 and to 0.06 m using Mo impurities and PAI 11 was demonstrated, for low temperature single RTP step processes, with excellent contact resistance and drive currents. 10,11 However, the mechanism by which Mo impurities assist the formation of C54 TiSi 2 remained unexplained. The presence of a ͑Ti, Mo͒Si 2 phase in the reaction of a Ti/Mo bilayer structure with Si, and epitaxial nucleation of C54 TiSi 2 on this phase was postulated, 12 but not demonstrated.…”

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confidence: 99%

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Mechanism of low temperature C54 TiSi2 formation bypassing C49 TiSi2: Effect of Si microstructure and Mo impurities on the Ti–Si reaction path

Kittl

Gribelyuk

Samavedam

1998

Applied Physics Letters

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X-ray diffraction, high resolution transmission electron microscopy, and resistivity measurements were used to demonstrate a modification of the Ti/Si reaction path consisting of direct nucleation followed by diffusion limited growth of low resistivity C54 TiSi2 without nucleation of high resistivity C49 TiSi2, for the reaction of Ti with Mo doped polycrystalline or Mo doped amorphous Si by rapid thermal processing at 650 °C. We also report the mechanism of early C54 nucleation. We demonstrate that MoSi2 and an unidentified silicide phase lattice matched to C54 TiSi2, with spacings of 4.15 and 2.26 Å, nucleate along the Ti/Si interface at early stages of the reaction and act as templates on which C54 TiSi2 nucleates and grows epitaxially. In contrast, the conventional phase sequence, nucleation and growth of C49 TiSi2 preceding nucleation of C54 TiSi2, was observed for the Ti/Mo doped single crystal (100) Si reaction and for all samples without Mo.

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Mechanism of low temperature C54 TiSi2 formation bypassing C49 TiSi2: Effect of Si microstructure and Mo impurities on the Ti–Si reaction path

Kittl

Gribelyuk

Samavedam

1998

Applied Physics Letters

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“…Silicides have been used in SALICIDE processes for several CMOS technology nodes [1][2][3][4][5]. For the 45 nm node, modifications or departures from conventional scaling schemes may be necessary, which will impact the integration constraints for silicides, their characteristics or even the way silicides are used in CMOS circuits.…”

Section: Introductionmentioning

confidence: 99%

Applications of Ni-based silicides to 45 nm CMOS and Beyond

et al. 2004

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This paper presents an overview of Ni-alloy (Ni, Ni-Pt and Ni-Ta) silicide development for the 45 nm node and beyond, including applications to self-aligned silicide (SALICIDE) processes, reaction with SiGe and strained Si on SiGe, and applications to fully silicided (FUSI) gates. Key SALICIDE issues addressed include the use of spike or low temperature rapid thermal processes (RTP) to control silicidation and junction leakage on small features, factors affecting the formation of epitaxial pyramidal NiSi 2 grains, and NiSi thermal stability and agglomeration kinetics. Alloying with Pt or Ta is shown to improve thermal stability of NiSi films, although with quite different behaviors. While Pt is incorporated predominantly in solution in NiSi, Ta segregates to the surface of the films. Ni-Pt alloy silicides were also found to achieve low sheet resistance on narrow gates, low contact resistivity and low junction leakage, making them attractive for CMOS applications. For the Ni/SiGe reaction, a narrower RTP process window for low sheet resistance and a lower activation energy for agglomeration were observed when compared to the Ni/Si reaction. The lower thermal stability was correlated to Ge segregation from the Ni(SiGe) films. The Ni/doped poly-Si reaction was studied for FUSI gate applications, showing a retardation of the silicidation kinetics for high B doses and a large pileup of dopants (for As, B or P) at the NiSi/SiO 2 interface due to dopant snowplow during silicidation. The work function (WF) of NiSi was observed to shift with the addition of dopants, effect attributed to modifications of the interface dipole by the pile-up of dopants. No significant degradation was observed when comparing gate oxide breakdown statistics for Ni FUSI to conventional poly-Si gates. The process window for a FUSI gate-last process (performed after S/D Ni silicidation) was evaluated showing a potential integration problem due to possible degradation of the S/D silicide during the FUSI gate reaction.

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“…However, using the conventional Ti-salicide process it is difficult to achieve a low resistance in narrow regions due to the incomplete phase transformation from the high-resistivity (phase C49) to the low-resistivity (phase C54) state. In order to enhance the phase transformation without increasing the silicidation temperature, the pre-amorphization implant (PAI) process has been proposed [7][8][9][10][11][12][13][14]. Using the PAI technique, Kittl et al [7] have fabricated and reported on 0.1 µm wide polysilicon Ti-salicide CMOS devices.…”

Section: Introductionmentioning

confidence: 99%

Comparative study of double ion implant Ti salicide and pre-amorphization implant Co salicide for ultra-large-scale integration applications

Chuang

Thei

Tsai

et al. 2002

Semicond. Sci. Technol.

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We have investigated the interesting double ion implant (DII) Ti-salicide and pre-amorphization implant (PAI) Co-salicide techniques for ultra-large-scale integration (ULSI) applications. The DII technique is combined with germanium (or arsenic) PAI and Si ion-mixing processes. The sheet resistances both of n + and p + polysilicons are decreased when the DII Ti-salicide and PAI Co-salicide techniques are used. Moreover, the incomplete phase transformation of Ti-salicide is not observed in 0.2 µm wide polysilicon devices with the Ge DII process. Furthermore, the n + /p-well junction leakage current is reduced when the Si ion-mixing process is used. Experimentally, based on the studied DII Ti-salicide and PAI Co-salicide techniques, high-performance 0.2 µm CMOS devices have been successfully fabricated.

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Salicides for 0.10 /spl mu/m gate lengths: a comparative study of one-step RTP Ti with Mo doping, Ti with pre-amorphization and Co process

Cited by 13 publications

References 1 publication

Mechanism of low temperature C54 TiSi2 formation bypassing C49 TiSi2: Effect of Si microstructure and Mo impurities on the Ti–Si reaction path

Mechanism of low temperature C54 TiSi2 formation bypassing C49 TiSi2: Effect of Si microstructure and Mo impurities on the Ti–Si reaction path

Applications of Ni-based silicides to 45 nm CMOS and Beyond

Comparative study of double ion implant Ti salicide and pre-amorphization implant Co salicide for ultra-large-scale integration applications

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