Reaction and Film Properties of Selective Titanium Silicide Low‐Pressure Chemical Vapor Deposition

Saito, Kimitoshi; Higashi, Youichirou; Amazawa, Takao; Arita, Yoshinobu

doi:10.1149/1.2055021

Cited by 14 publications

(2 citation statements)

References 4 publications

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“…The results have also been reported in Ref. 12 and can be summarized as follows. Initially, the decomposition rate of SiH4 was low while that of TiCl4 was high.…”

Section: Methodssupporting

confidence: 61%

Cause of Aligned‐Orientation Growth of Titanium Silicide in Plasma Enhanced Chemical Vapor Deposition

Saito

Arita

1996

J. Electrochem. Soc.

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Growth characteristics in initial stages of an aligned-orientation growth of epitaxial C49-structure TiSi5 grains selectively deposited by plasma-enhanced chemical vapor deposition (PECVD) are studied and compared with polycrystal growth of suicides in low-pressure chemical vapor deposition (LPCVD). PEC\TD was performed using TiCl4/Ar/H2 gases with and without SiH4 at about 700°C on (001)-oriented Si substrates. Ti atoms diffused into the silicon from the surface in the initial growth stages. The density of Ti atoms increased and epitaxial silicide grains were first formed when the density reached that of the disilicide. In LPCVD using TiC14 and SiH4, island grains of a Ti-rich silicide (Ti5Si4) and a disilicide with multiple orientations were formed in the initial stages. The Ti-rich silicide was deposited due to the high rate of Cl reduction from TiC14 by Si of the substrate and low SiH4 decomposition rate. In the succeeding deposition, the SiH4 decomposition rate increased and the Ti-rich suicide was changed into the C54-structure TiSi2. The difficulty of epitaxial growth in LPCVD results from the growth of multiple silicides, island growth, and stoichiometry change. Above difference in growth features between PECVD and LPCVD is caused by a difference in behaviors of Ti diffusion into silicon. The Ti-atom diffusion plays an important role in the aligned-orientation growth in PECVD.

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“…The results have also been reported in Ref. 12 and can be summarized as follows. Initially, the decomposition rate of SiH4 was low while that of TiCl4 was high.…”

Section: Methodssupporting

confidence: 61%

Cause of Aligned‐Orientation Growth of Titanium Silicide in Plasma Enhanced Chemical Vapor Deposition

Saito

Arita

1996

J. Electrochem. Soc.

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“…The CVD process was first introduced by Tedrow et al 7 in 1985, and it has attracted considerable interest from researchers in U.S., Japan, and France. [8][9][10][11][12][13][14][15][16] Silicides are formed on heavily doped source/drain regions and polycrystalline silicon gates. For the conventional SALICIDE process, the effects of dopants on the formation and characteristics of silicides have been extensively studied.…”

mentioning

confidence: 99%

Effects of Arsenic Doping on Chemical Vapor Deposition of Titanium Silicide

Fang¹,

Öztürk²,

Seebauer

et al. 1999

J. Electrochem. Soc.

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Titanium silicide (TiSi 2 ) has long been used in complementary metal oxide silicon (CMOS) integrated circuits because of its low resistivity and compatibility with standard processes. 1 With the scaling of device dimensions into the deep submicron regime, two problems related to the conventional self-aligned silicide (SALICIDE) process have emerged. The first problem is the so-called narrow-line effect which describes the difficulty in conversion of TiSi 2 from the high resistivity C49 phase into the low resistivity C54 phase on narrow polysilicon lines. 2 Several new growth methods have been suggested to solve this problem, including the use of titanium alloys 3 and molybdenum implants. 4 The second problem is the silicon substrate consumption during silicide formation, which makes the SALICIDE process incompatible with ultrashallow junctions. Metal oxide semiconductor field effects transistor (MOSFETs) with elevated source/ drain structures have been proposed to address this problem. 5,6 Selective chemical vapor deposition (CVD) of TiSi 2 has been proposed as an alternative process to form contacts to ultrashallow junctions without silicon consumption. It has also been suggested that C49-C54 conversion occurs more readily for this process although this area still lacks an in-depth investigation. The CVD process was first introduced by Tedrow et al. 7 in 1985, and it has attracted considerable interest from researchers in U.S., Japan, and France. [8][9][10][11][12][13][14][15][16] Silicides are formed on heavily doped source/drain regions and polycrystalline silicon gates. For the conventional SALICIDE process, the effects of dopants on the formation and characteristics of silicides have been extensively studied. For TiSi 2 , several general remarks can be made: (i) TiSi 2 growth rate depends on dopant type and concentration. The growth rate is highest on undoped and borondoped substrates, lower on heavily phosphorous-doped substrates, and lowest on heavily arsenic-doped substrates 17,18 ; (ii) Ti reacts with boron and arsenic to form stable compounds such as TiAs and TiB 2 , which makes TiSi 2 unsuitable as a dopant out-diffusion source to form junctions [18][19][20] ; (iii) TiSi 2 films formed on arsenic-doped substrates are thermally less stable. 21 Most studies on CVD TiSi 2 have concentrated mainly on understanding the first principles of the process on undoped or moderately doped substrates, or on heavily doped silicon with an undoped silicon epitaxial interlayer. 22,23 Only a few studies exist concerning TiSi 2 deposition on heavily doped substrates. [24][25][26][27] It appears, however, that arsenic does effect deposition and consumption. 25 In a recent report, 28 this group presented experimental results on TiSi 2 deposition on heavily boron-doped substrates. It was conclud-ed that implanted boron does not have a strong influence on the deposition process. Shallow p ϩ -n junctions (X j ϭ 1000 Å) with 800 Å thick TiSi 2 contacts were successfully fabricated. It was also shown by a preliminary experiment...

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