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Growth of extra-thin ordered aluminum films on Si(110) surfaces
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Surface Science Letters 277 (1992) L77-LS3 North-Holland
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surface science letters
Surface Science Letters
Growth of extra-thin ordered aluminum films on Si(l10) surfaces A.V. Zotov a, E.A. Khramtsova a, V.G. Lifshits a, A.T. Kharchenko b, S.V. Ryzhkov b and A.N. Demidchik b a Institute of Automation and Control Processes, Russian Academy of Sciences, Vladivostok 690032, Russian Federation b Far East State Unitiersity, Vladivostok
690022, Russian Federation
Received 11 May 1992; accepted for publication 5 August 1992
The formation of surface structures upon Al deposition onto a Si(ll0) surface was studied by LEED and AES. The “4 X 6”, “1 X Y’, 2 X 1, 1 X 1 ordered Si(llO)-Al surface phases and epitaxial Al(110) domains were observed depending on Al coverage and substrate temperature. The formation phase diagram was drawn for the AI/Si(llO) system.
The interaction of aluminum with silicon is of current scientific and technological interest since aluminum is the most used metal for metallization in Si device technology. Among other questions, the initial stages of metal/silicon interface formation have recently attracted the growing attention of researchers. There have been many investigations on the submonolayer surface phases in AI/Si(lll) systems. It has been shown that, depending on Al coverage and heat treatment, AI forms the (6 X &IR30”,
phases, (2 x 21, (2 x 31, (4 x 51, (1 x 7) and c(4 x 121, under various conditions, 20 < T < 700°C and 0 < 0, < 1 ML, and have proposed structure models for (2 x 2) and (2 x 3) phases. To our knowledge, no results have been reported on the submonolayer AI/Si(llO) interface. This reflects the overall situation that in contrast to the sufficient amount of literature on 700 650 600
*u_ 550 ii
E
soo-
f
450 -
0.5
1
Al coverage, ML Fig. 1. Two-dimensional
0 1992 - Elsevier Science Publishers B.V. All rights reserved
phase diagram of the AI/Si(llO)
A.V. Zoto~’ et al. / Growth of extra-thin ordered aluminum films on Si(ll0)
Si(ll1) and SKlOO) surfaces much less has been done on Si(llO), although the latter surface has received recently increasing interest [U-36]. In particular, it has been shown that the “2 x 16” structure is the only clean surface structure while other reconstructions observed, (4 x 51, (2 x 11, (5 x 1) and (7 x 11, are induced by small amounts of nickel impurities [15-181. The Si(llO)-“2 X 16”
surfaces
surface has been elucidated as one consisting of a up and down sequence of terraces with a step height of one Si(ll0) bulk layer spacing [17,19,20]. As for the interaction of the foreign atoms with the Si(ll0) surface, Ni [15,17,18,21-271, Ge [28], Sb [29,301, H [17,31,32], Cl [331, Au [34], Se [351 and Bi [36] submonolayer films have been investigated hitherto.
0 l l l l 0
l l 0 l l
Fig. 2. (a) LEED pattern (electron energy E = 76 eV) from the “4 X 6” phase (0.25 ML at 650°C). Sketches of LEED patterns (reciprocal lattices) for (b) two-domain and (cl single-domain “4 x 6” structures. Open circles are fundamental spots, closed circles are fractional-order spots.
A. V. Zotoc et al. / Growth of extra-thin ordered aluminum films on Si(llO)
In the present Letter, several ordered Al-induced structures have been observed on the Si(ll0) surface depending on the coverage and substrate temperature during Al deposition. The onset of epitaxial Al(110) growth on top of Si(llO)-Al surface phases has been detected. Experiments were carried out in an ultrahigh-vacuum chamber with a base pressure of 2 X 10-l” Torr equipped with a cylindrical-mirror
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analyzer and LEED optics. The substrates were rectangular Si bars of 0.06 R * cm AI-doped and 20 R. cm P-doped Si(ll0) of 15 x 5 x 0.5 mm3. Before insertion into the chamber, the samples were cleaned in organic solvents. Finally, the native oxide and residual carbon contaminations were removed by heating the samples at 1200°C for 3 min. After cleaning, AES analysis indicated no detectable contaminations at the surface. The
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Fig. 3. (a) LEED pattern (E = 76 eV) from “1 x 9” phase (0.5 ML at 650°C). Sketches of the LEED patterns (reciprocal lattices) for (b) two-domain and (c) single-domain “1 X 9” structures.
ordered aluminum films on Sic1 10) surfaces
0
0
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(b) Fig. 4. (a)
LEED pattern (E = 96 eV) from the (2
X
1) phase (0.8 ML at 450°C) and (b) sketch of the LEED pattern.
cleaned samples displayed a LEED pattern which was identified as “2 X 16” [l&16] with faint features of the (1 X 5) structure [37]. Al was deposited by heating a tungsten filament. The background pressure during Al deposition was below 8 x lo-” Torr. The deposition rate was in the 0.05 to 0.5 ML/min range. The Al coverage was determined from the AES AlLW (68 eV> to SiLW (92 eV> peak height ratio within the framework of the model of thin homogeneous Al layers on a Si substrate [38]. The formation two-dimensional phase diagram of the Al/Si(llO) system as deduced from LEED-AES observations is shown in fig. 1. In the experiment, Al was deposited step by step at a given substrate temperature. After each step, the sample was cooled to room temperature for LEED-AES observations. When Al is deposited onto the Si(ll0) substrate held at 600 to 700°C two well-defined Al-induced reconstructions are observed successively. The first one is the two-domain “4 X 6” structure which exists at Al coverages from 0.16 to 0.3 ML. (1 ML is defined as the density of the topmost atoms of the unreconstructed Si(llO1 plane, i.e., 9.59 x 1014 cme2). The quotes indicate that this reconstruction is not aligned along the bulk symmetry axes. It can be expressed more strictly in matrix notation as (i :I. Fig. 2a shows
the LEED pattern from this surface. Figs. 2b and 2c show the sketches of the LEED patterns (reciprocal lattices) for two-domain and single-domain phases, respectively. When the Al coverage exceeds the value of 0.3 ML, the “4 x 6” structure changes to the two-domain “1 X 9” structure, (i _T) in matrix notation (fig. 3). The “1 x 9” phase is completed at a saturated coverage of 0.5 ML. No additional Al
Fig. 5. LEED pattern (E = 76 eV) from the (1 X 1) phase (1.0 ML at 400°C).
A. V. Zotou et al. / Growth of extra-thin ordered aluminum films on Si(ll0)
can be deposited indicating that the sticking coefficient decreases abruptly beyond 0.5 ML. The Al growth at temperatures from 600 down to about 500°C is similar to that described above,
surfaces
i.e., successive formation of “4 X 6” and “1 x 9” phases is observed. However the critical Al coverages at which the structural transformation from “4 x 6” to “1 x 9” occurs shifts towards higher
Fig. 6. (a) LEED pattern (E = 76 eV) from the surface of a 4 ML thick Al layer grown at 400°C. (b) Schematic drawing of the diffraction pattern shown in (a). Open circles arc Si(llO)l x 1 reflections, the crosses denote the missing spots of the Si(llO)l x 1 pattern. Stars show the expected pysitions of the reflections from the AhllO) surface (AhllO) surface-lattice unit cell is rectangular with unit vectors of 2.96 and 4.05 A, i.e., 1.34 times smaller than corresponding vectors of the SifllO) surface). Segments represent the observed Al(110) reflections. (c) LEED pattern (E = 76 eV) from the surface of 4 ML thick Al layer grown on the “1 X 9” phase at 400°C.
A. V. Zotoc et al. / Growth of extra-thin ordered aluminum films on Si(ll0)
coverages. The LEED patterns from “4 X 6” and “1 x 9” phases become gradually less sharp and bright with decreasing growth temperature. Upon deposition of Al at about 430°C the “4 x 6” and “1 x 9” LEED patterns are not observed but a new structure, (2 X 1) (fig. 41, appears at about 0.5 ML and occurs up to Sb saturation coverage at about 1 ML. The (2 X 11 phase is found to exist in a very narrow temperature interval from about 430 to 460°C. Upon Al deposition below 430°C a (1 X 1) LEED pattern is observed at coverages beyond 0.5 ML (fig. 5). As one can see, the (1 X 1) LEED pattern is characterized by the extinction of all fractional-order reflections and several integerorder ones. At these growth temperatures, the Al layer does not saturate at a certain coverage and Al deposition onto the (1 x 1) phase results in the appearance of the LEED spots corresponding to epitaxial Al(110) (figs. 6a and 6b). The epitaxial Ah1101 can be grown on the “1 X 9”reconstructed Si(llO)-Al surface also (fig. 6~1. In the latter case, the “1 X 9” phase is formed at 650°C then the substrate temperature is decreased to 400°C and the Al deposition is continued. The AN1101 reflections are strongly elongated along the direction parallel to the short vector of the (11O)l X 1 unit cell indi_cating a more extended periodicity along the [llO] direction compared to that along the [OOl] direction. A similar observation was reported by Hasan et al. [39] for the growth of epitaxial Al(110) domains on a Si(100) surface. Another common feature in the Al(110) LEED patterns of his work and ref. [39] is the extinction of selected reflections in the diffraction patterns similar to the case of bulk diffraction from an fee lattice. Hasan et al. [39] suggested that the surface contains domains that are separated by atomic or multiatomic steps and incident LEED electrons scattering occurs from several atomic layers in the direction normal to the surface. Thus, the third Laue condition becomes important and the reciprocal two-dimensional rods shrink to spots forming a three-dimensional reciprocal lattice. Al deposition at room temperature CRT) grad-
surfaces
ually enhances the background and eliminates all diffraction spots in the LEED pattern. This result indicates the formation of the disordered film. The annealing of the RT Al deposit produces one of the phases described above depending on Al coverage and annealing temperature. For example, annealing of a several ML thick Al film produces successively a (1 X 1) phase at 4OO”C,a (2 x 1) phase at 450°C and “1 X 9” phase at 600°C. In conclusion, we have shown that depending on Al coverage and heat treatments Al deposition on Si(ll0) forms “4 X 6”, “1 X 9”, (2 X l), (1 X 1) surface phases and epitaxial Al(110) domains. We have determined a formation diagram of these surface structures. The authors would like to acknowledge Dr. A.A. Saranin for his support to the present work.
References
111J.J. Lander and J. Morrison, Surf. Sci. 2 (1964) 553. 121R.J. Hamers, Phys. Rev. B 40 (1989) 1657. [31 T. Kinoshita, S. Kono and T. Sagawa, Phys. Rev. B 32 (1985) 2714. [41 T. Kinoshita, S. Kono and T. Sagawa, Solid State Commun. 56 (198.5) 681. [51 G.V. Hansson, R.Z. Bachrach, R.S. Bauer and P. Chiaradia, Phys. Rev. Lett. 46 (1981) 1033. l61 RIG. Uhrberg, G.V. Hansson, J.M. Nicholls, P.E.S. Persson and S.A. Flodstriim, Phys. Rev. B 31 (1985) 3805. [71 J.M. Nicholls, B. Reihl and J.E. Northrup, Phys. Rev. B 35 (1987) 4137. and J.E. Demuth, J. Vat. Sci. Technol. A 6 (1988) 512. 191 R.J. Hammers, J. Vat. Sci. Technol. B 6 (1988) 1462. J. Anderson, D.J. Frankel DO1 M.K. Kelly, G. Margaritondo, and G.J. Lapeyre, J. Vat. Sci. Technol. A 4 (1986) 1396. [ill H. Huang, S.Y. Tong, W.S. Yang, H.D. Shih and F. Jona, Phys. Rev. B 42 (1990) 7483. 1121J.E. Northrup, Phys. Rev. Lett. 57 (1984) 683. Surf. Sci. 209 [131 T. Ide, T. Nishimori and T. Ichinokawa, (1989) 335. 1141J. Nogami, A.A. Baski and C.F. Quate, Phys. Rev. B 44 (1991) 1415. [151 T. Ichinokawa, H. Ampo, S. Miura and A. Tamura, Phys. Rev. B 31 (1985) 5183. l161Y. Yamamoto, S. Ino and T. Ichikawa, Jpn. J. Appl. Phys. 25 (1986) L331. 1171 H. Ampo, S. Miura, K. Kato, Y. Ohkawa and A. Tamura, Phys. Rev. B 34 (1986) 2329. Appl. Surf. Sci. 33/34 (19881 21. 1181 B.A. Nesterenko,
[81 R.J. Hamers
A. V. ZotoL’ et al. / Growth of extra-thin ordered aluminum films on Si(ll0) [19] E.J. van Loenen, D. Dijkkamp and A.J. Hoeven, J. Microsc. 152 (1988) 487. [20] A.J. Hoeven, D. Dijkkamp, E.J. van Loenen and P.J.G.M. van Hooft, Surf. Sci. 211/212 (19891 165. [21] B.A. Nesterenko and AI. Shkrebtii, Surf. Sci. 213 (19891 309. [22] AI. Shkrebtii, C.M. Bertoni, R. Del Sole and B.A. Nesterenko, Surf. Sci. 239 (19901 227. [23] A.E. Dolbak, B.Z. Olshanetsky, S.I. Stenin, S.A. Teyes and T.A. Gavrilova, Surf. Sci. 218 (1989) 37. [24] A.E. Dolbak, B.Z. Olshanetsky, S.I. Stenin and S.A. Teyes, Surf. Sci. 247 (19911 32. [25] H. Neddermeyer and St. Tosch, Phys. Rev. B 38 (19881 5784. [26] H. Neddermeyer and St. Tosch, J. Microsc. 152 (19881 149. [27] R.S. Becker, B.S. Swartzentruber and J.S. Vickers, J. Vat. Sci. Technol. A 6 (1988) 472. [28] S. Miura, K. Kato, T. Ide and T. Ichinokawa, Surf. Sci. 191 (1987) 259. [29] D.H. Rich, G.E. Franklin, F.M. Leibsle, T. Miller and T.-C. Chiang, Phys. Rev. B 40 (1989) 11804.
surfaces
1301A.V. Zotov, V.G. Lifshits and A.N. Demidchik,
Surf. Sci. Lett. 274 (1992) L.583. 1311 R. Butz, E.M. Oelig, H. Ibach and H. Wagner, Surf. Sci. 147 (1984) 343. [321 C. Kleint, Vacuum 36 (1986) 267. [331 N. Aoto, E. Ikawa and Y. Kurogi, Surf, Sci. 199 (1988) 408. [341 A.K. Green and E. Bauer, Surf. Sci. 103 (1981) L127. 1351 B.N. Dev, T. Thundat and W.M. Gibson, J. Vat. Sci. Technol. A 3 (19851 946. [361 T. Oyama, S. Ohi, A. Kawazu and G. Tominaga, Surf. Sci. 109 (1981) 82. [371 B.Z. Olshanetsky and A.A. Shklyaev, Surf. Sci. 67 (19771 581. [381 M.P. Seach, in: Practical Surface Analysis by Auger and X-Ray Photoelectron Spectroscopy, Eds. D. Briggs and M.P. Seach (Wiley, New York, 1983) [Russian translation: (Mir, Moscow, 1987) p. 2361. J.-E. Sundgren and G.V. 1391 M.-A. Hasan, G. Radnoczi, Hansson, Surf. Sci. 236 (1990153.
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Surface Science Letters 277 (1992) L77-LS3 North-Holland
:......,.A.
..
.,....
..
surface science letters
Surface Science Letters
Growth of extra-thin ordered aluminum films on Si(l10) surfaces A.V. Zotov a, E.A. Khramtsova a, V.G. Lifshits a, A.T. Kharchenko b, S.V. Ryzhkov b and A.N. Demidchik b a Institute of Automation and Control Processes, Russian Academy of Sciences, Vladivostok 690032, Russian Federation b Far East State Unitiersity, Vladivostok
690022, Russian Federation
Received 11 May 1992; accepted for publication 5 August 1992
The formation of surface structures upon Al deposition onto a Si(ll0) surface was studied by LEED and AES. The “4 X 6”, “1 X Y’, 2 X 1, 1 X 1 ordered Si(llO)-Al surface phases and epitaxial Al(110) domains were observed depending on Al coverage and substrate temperature. The formation phase diagram was drawn for the AI/Si(llO) system.
The interaction of aluminum with silicon is of current scientific and technological interest since aluminum is the most used metal for metallization in Si device technology. Among other questions, the initial stages of metal/silicon interface formation have recently attracted the growing attention of researchers. There have been many investigations on the submonolayer surface phases in AI/Si(lll) systems. It has been shown that, depending on Al coverage and heat treatment, AI forms the (6 X &IR30”,
phases, (2 x 21, (2 x 31, (4 x 51, (1 x 7) and c(4 x 121, under various conditions, 20 < T < 700°C and 0 < 0, < 1 ML, and have proposed structure models for (2 x 2) and (2 x 3) phases. To our knowledge, no results have been reported on the submonolayer AI/Si(llO) interface. This reflects the overall situation that in contrast to the sufficient amount of literature on 700 650 600
*u_ 550 ii
E
soo-
f
450 -
0.5
1
Al coverage, ML Fig. 1. Two-dimensional
0 1992 - Elsevier Science Publishers B.V. All rights reserved
phase diagram of the AI/Si(llO)
A.V. Zoto~’ et al. / Growth of extra-thin ordered aluminum films on Si(ll0)
Si(ll1) and SKlOO) surfaces much less has been done on Si(llO), although the latter surface has received recently increasing interest [U-36]. In particular, it has been shown that the “2 x 16” structure is the only clean surface structure while other reconstructions observed, (4 x 51, (2 x 11, (5 x 1) and (7 x 11, are induced by small amounts of nickel impurities [15-181. The Si(llO)-“2 X 16”
surfaces
surface has been elucidated as one consisting of a up and down sequence of terraces with a step height of one Si(ll0) bulk layer spacing [17,19,20]. As for the interaction of the foreign atoms with the Si(ll0) surface, Ni [15,17,18,21-271, Ge [28], Sb [29,301, H [17,31,32], Cl [331, Au [34], Se [351 and Bi [36] submonolayer films have been investigated hitherto.
0 l l l l 0
l l 0 l l
Fig. 2. (a) LEED pattern (electron energy E = 76 eV) from the “4 X 6” phase (0.25 ML at 650°C). Sketches of LEED patterns (reciprocal lattices) for (b) two-domain and (cl single-domain “4 x 6” structures. Open circles are fundamental spots, closed circles are fractional-order spots.
A. V. Zotoc et al. / Growth of extra-thin ordered aluminum films on Si(llO)
In the present Letter, several ordered Al-induced structures have been observed on the Si(ll0) surface depending on the coverage and substrate temperature during Al deposition. The onset of epitaxial Al(110) growth on top of Si(llO)-Al surface phases has been detected. Experiments were carried out in an ultrahigh-vacuum chamber with a base pressure of 2 X 10-l” Torr equipped with a cylindrical-mirror
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analyzer and LEED optics. The substrates were rectangular Si bars of 0.06 R * cm AI-doped and 20 R. cm P-doped Si(ll0) of 15 x 5 x 0.5 mm3. Before insertion into the chamber, the samples were cleaned in organic solvents. Finally, the native oxide and residual carbon contaminations were removed by heating the samples at 1200°C for 3 min. After cleaning, AES analysis indicated no detectable contaminations at the surface. The
0
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Fig. 3. (a) LEED pattern (E = 76 eV) from “1 x 9” phase (0.5 ML at 650°C). Sketches of the LEED patterns (reciprocal lattices) for (b) two-domain and (c) single-domain “1 X 9” structures.
ordered aluminum films on Sic1 10) surfaces
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0
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0
0
(b) Fig. 4. (a)
LEED pattern (E = 96 eV) from the (2
X
1) phase (0.8 ML at 450°C) and (b) sketch of the LEED pattern.
cleaned samples displayed a LEED pattern which was identified as “2 X 16” [l&16] with faint features of the (1 X 5) structure [37]. Al was deposited by heating a tungsten filament. The background pressure during Al deposition was below 8 x lo-” Torr. The deposition rate was in the 0.05 to 0.5 ML/min range. The Al coverage was determined from the AES AlLW (68 eV> to SiLW (92 eV> peak height ratio within the framework of the model of thin homogeneous Al layers on a Si substrate [38]. The formation two-dimensional phase diagram of the Al/Si(llO) system as deduced from LEED-AES observations is shown in fig. 1. In the experiment, Al was deposited step by step at a given substrate temperature. After each step, the sample was cooled to room temperature for LEED-AES observations. When Al is deposited onto the Si(ll0) substrate held at 600 to 700°C two well-defined Al-induced reconstructions are observed successively. The first one is the two-domain “4 X 6” structure which exists at Al coverages from 0.16 to 0.3 ML. (1 ML is defined as the density of the topmost atoms of the unreconstructed Si(llO1 plane, i.e., 9.59 x 1014 cme2). The quotes indicate that this reconstruction is not aligned along the bulk symmetry axes. It can be expressed more strictly in matrix notation as (i :I. Fig. 2a shows
the LEED pattern from this surface. Figs. 2b and 2c show the sketches of the LEED patterns (reciprocal lattices) for two-domain and single-domain phases, respectively. When the Al coverage exceeds the value of 0.3 ML, the “4 x 6” structure changes to the two-domain “1 X 9” structure, (i _T) in matrix notation (fig. 3). The “1 x 9” phase is completed at a saturated coverage of 0.5 ML. No additional Al
Fig. 5. LEED pattern (E = 76 eV) from the (1 X 1) phase (1.0 ML at 400°C).
A. V. Zotou et al. / Growth of extra-thin ordered aluminum films on Si(ll0)
can be deposited indicating that the sticking coefficient decreases abruptly beyond 0.5 ML. The Al growth at temperatures from 600 down to about 500°C is similar to that described above,
surfaces
i.e., successive formation of “4 X 6” and “1 x 9” phases is observed. However the critical Al coverages at which the structural transformation from “4 x 6” to “1 x 9” occurs shifts towards higher
Fig. 6. (a) LEED pattern (E = 76 eV) from the surface of a 4 ML thick Al layer grown at 400°C. (b) Schematic drawing of the diffraction pattern shown in (a). Open circles arc Si(llO)l x 1 reflections, the crosses denote the missing spots of the Si(llO)l x 1 pattern. Stars show the expected pysitions of the reflections from the AhllO) surface (AhllO) surface-lattice unit cell is rectangular with unit vectors of 2.96 and 4.05 A, i.e., 1.34 times smaller than corresponding vectors of the SifllO) surface). Segments represent the observed Al(110) reflections. (c) LEED pattern (E = 76 eV) from the surface of 4 ML thick Al layer grown on the “1 X 9” phase at 400°C.
A. V. Zotoc et al. / Growth of extra-thin ordered aluminum films on Si(ll0)
coverages. The LEED patterns from “4 X 6” and “1 x 9” phases become gradually less sharp and bright with decreasing growth temperature. Upon deposition of Al at about 430°C the “4 x 6” and “1 x 9” LEED patterns are not observed but a new structure, (2 X 1) (fig. 41, appears at about 0.5 ML and occurs up to Sb saturation coverage at about 1 ML. The (2 X 11 phase is found to exist in a very narrow temperature interval from about 430 to 460°C. Upon Al deposition below 430°C a (1 X 1) LEED pattern is observed at coverages beyond 0.5 ML (fig. 5). As one can see, the (1 X 1) LEED pattern is characterized by the extinction of all fractional-order reflections and several integerorder ones. At these growth temperatures, the Al layer does not saturate at a certain coverage and Al deposition onto the (1 x 1) phase results in the appearance of the LEED spots corresponding to epitaxial Al(110) (figs. 6a and 6b). The epitaxial Ah1101 can be grown on the “1 X 9”reconstructed Si(llO)-Al surface also (fig. 6~1. In the latter case, the “1 X 9” phase is formed at 650°C then the substrate temperature is decreased to 400°C and the Al deposition is continued. The AN1101 reflections are strongly elongated along the direction parallel to the short vector of the (11O)l X 1 unit cell indi_cating a more extended periodicity along the [llO] direction compared to that along the [OOl] direction. A similar observation was reported by Hasan et al. [39] for the growth of epitaxial Al(110) domains on a Si(100) surface. Another common feature in the Al(110) LEED patterns of his work and ref. [39] is the extinction of selected reflections in the diffraction patterns similar to the case of bulk diffraction from an fee lattice. Hasan et al. [39] suggested that the surface contains domains that are separated by atomic or multiatomic steps and incident LEED electrons scattering occurs from several atomic layers in the direction normal to the surface. Thus, the third Laue condition becomes important and the reciprocal two-dimensional rods shrink to spots forming a three-dimensional reciprocal lattice. Al deposition at room temperature CRT) grad-
surfaces
ually enhances the background and eliminates all diffraction spots in the LEED pattern. This result indicates the formation of the disordered film. The annealing of the RT Al deposit produces one of the phases described above depending on Al coverage and annealing temperature. For example, annealing of a several ML thick Al film produces successively a (1 X 1) phase at 4OO”C,a (2 x 1) phase at 450°C and “1 X 9” phase at 600°C. In conclusion, we have shown that depending on Al coverage and heat treatments Al deposition on Si(ll0) forms “4 X 6”, “1 X 9”, (2 X l), (1 X 1) surface phases and epitaxial Al(110) domains. We have determined a formation diagram of these surface structures. The authors would like to acknowledge Dr. A.A. Saranin for his support to the present work.
References
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