Figures from "Atomically-Resolved Studies of the Chemistry and Bonding at Silicon Surfaces", by Y. Wang and R.J. Hamers, Chemical Reviews, vol. 96, p. 1261-1290 (1996).

Figure 2

STM images of clean Si(001) surface probing the filled surface states and the empty surface states:
(2a) Vsample = -2.0 V and (2b) Vsample = 2.3 V.
Itunnel = 0.2 nA; dimensions = 23 Å x 77 Å.


Figure 3

Structural model of hydrogen on Si(001), showing monohydride, hemihydride, and (3x1) structures.


Figure 4

STM image showing clean and monohydride dimers on Si(001), prepared by thermal dissociation of disilane at 660 K. Area = 31 Å x 52 Å; Vsample = -3.0 V; Itunnel = 0.5 nA.


** Figure 4 from Wang, Y.; Bronikowski, M.J.; Hamers, R.J. Surf. Sci. 1994, 311, 64 and Wang, Y.; Bronikowski, M.J.; Hamers, R.J. J. Vac. Sci. Technol. A 1994, 12, 2051.

Figure 5

Sequential images of Si(001) obtained while simultaneously dosing with disilane at room temperature: (5a) exposure of 0.1 langmuir; other images are taken 230 s apart. Surface area = 200 Å x 200 Å; Vsample = -2.2 V; Itunnel = 0.5 nA.**


** Figure 5 from Wang, Y.; Bronikowski, M.J.; Hamers, R.J. Surf. Sci. 1994, 311, 64.

Figure 6

Sequential images of Si(001) surface showing adsorption of SiH2 and SiH3 and the dissociation reaction SiH3(ads) --> SiH2(ads) + H(ads):
(6a) clean Si(001) surface before exposure to Si2H6;
(6b) same area as in 6a after exposure to 0.1 langmuir Si2H6 at 300 K, showing adsorbed SiH2 group (left) and SiH3 group (right);
(6c) same region as in 6a and 6b, acquired 8 minutes after 6b, showing the shift in bonding location as SiH3 group dissociates to SiH2 and the appearance of atomic-sized depression due to H atom adsorption. Area = 47 Å x 47 Å; Vsample = -2.2 V; Itunnel = 0.5 nA.**


** Figure 6, from Wang, Y.; Bronikowski, M.J.; Hamers, R.J. Surf. Sci. 1994, 311, 64.

Figure 7

Atomic-resolution STM image and schematic model showing different dimer configurations observed during decomposition of Si2H6 on Si(001). STM image (top) taken after exposure to 0.2 langmuir of Si2H6 at 300 K and subsequent anneal at 470 K for 2 min, showing different bonding locations of three types of dimer structures. Area = 70 Å x 70 Å; Vs = -2.0 V; It = 0.5 nA. Bottom: model for four possible Si=Si ad-dimer structures which achieve 4-fold coordination for adsorbing silicon atoms. The structures shown in A, T, and NRD are found in the above figure.**


** Figure 7 from Wang, Y.; Bronikowski, M.J.; Hamers, R.J. Surf. Sci. 1994, 311, 64.

Figure 8

Model depicting the proposed mechanism for the decomposition of Si2H6 on Si(001).**


** Figure 8 from Wang, Y.; Bronikowski, M.J.; Hamers, R.J. Surf. Sci. 1994, 311, 64.

Figure 9

Model of Cl on Si(001) surface, showing different structures.


Figure 11

Structural model for the (3x1) structure of Br on Si(001).


Figure 12

Proposed bonding geometries for H2O/Si(001) and formation of "C"-type defects.**


** Figure 12 from Chander, M.; Li, Y.Z.; Patrin, J.C.; Weaver, J.H. Phys. Rev. B 1993, 48.

Figure 13

(13a) Large-scale STM image of phosphorous-terminated Si(001) surface, showing spontaneous island formation and the presence of line defects cutting perpendicular to the dimer rows. Vsample = -2.0 V; Itunnel = 0.2 nA; dimensions = 1150 Å x 1200 Å. (13b) Atomic-resolution STM image showing detailed appearance of line defects and the characteristic appearance of P-P dimers and P-Si dimers. Vsample = -0.2 V; Itunnel = 0.2 nA; dimensions = 80 Å x 90 Å**


** Figure 13 from Wang, Y.; Chen X.; Hamers, R.J. Phys. Rev. B 1994, 50, 4534.

Figure 14

Structural models and bond lengths for Si=Si, P-P, and Si-P dimers on Si(001), including top and side views.**


** Figure 14 from Wang, Y.; Chen X.; Hamers, R.J. Phys. Rev. B 1994, 50, 4534.

Figure 15

(15a) Large-scale STM image of Si(001) surface with partial P coverage. Note the mottled appearance due to Si and P atoms and the absence of line defects. Vsample = -2.15 V; Itunnel = 0.2 nA; dimensions = 1000 Å x 1000 Å.
(15b) High-resolution image of partially-P-terminated surface showing Si=Si, Si-P, and P-P dimers. Some Si=Si dimers are indicated with arrows; Si-P, and P-P dimers can be found in numerous locations. Vsample = -2.2 V; Itunnel = 0.2 nA; dimensions = 95 Å x 95 Å.**


** Figure 15 from Wang, Y.; Chen X.; Hamers, R.J. Phys. Rev. B 1994, 50, 4534.

Figure 16

Statistical analysis of the surface chemical composition obtained by counting the number of Si=Si, Si-P, and P-P dimers. Black bars indicate the experimental results, while shaded graphs show the predicted probability distribution for a completely- random alloy containing 866 P atoms and 270 Si atoms.**


** Figure 16 from Wang, Y.; Chen X.; Hamers, R.J. Phys. Rev. B 1994, 50, 4534.

Figure 18

(18a and 18b) STM images of Si(001) exposed to 180 langmuir of B2H6 at 300 K. Several patches of reacted Si regions are indicated by arrows:
(18a) Dimension = 170 Å x 128 Å, Vsample = -3.0 V, Itunnel = 0.3 nA;
(18b) Dimension = 80 Å x 55 Å, Vsample = -2.0 V, Itunnel = 0.3 nA.
(18c) IR spectrum taken after exposing Si(001) to 28 langmuir of B2H6 at room temperature.**


** Figure 18 from Wang, Y.; Shan, J.; Hamers, R.J. J. Vac. Sci. Technol. B 1996, in press and Wang, Y.; Shan, J.; Hamers, R.J. J. Phys. Chem. 1996, in press.

Figure 19

(19a) STM image of diborane-exposed surface showing formation of reconstructed islands and patchy reconstruction of substrate terrace. Vsample = -2.0 V, Itunnel = 0.2 nA; dimensions = 485 Å x 485 Å.
(19b) High-resolution image of boron-induced reconstructions on Si(001) surface, Vsample = -2.0 V; Itunnel = 0.2 nA; dimensions = 48 Å x 60 Å.**


** Figure 19 from Wang, Y.; Hamers, R.J.; Kaxiras, E. Phys. Rev. Lett. 1995, 74, 403 and Wang, Y.; Hamers, R.J. J. Vac. Sci. Technol. A 1995, 13, 1431.

Figure 20

Structural model of boron-induced reconstruction on Si(001), showing boron atoms in second layer (black) with Si dimers on top.**


** Figure 20 from Wang, Y.; Hamers, R.J.; Kaxiras, E. Phys. Rev. Lett. 1995, 74, 403 and Wang, Y.; Hamers, R.J. J. Vac. Sci. Technol. A 1995, 13, 1431.

Figure 21

STM images of B/Si(001) surfaces exposed to 0.05 langmuir of Si2H6 at 300 K, showing the higher chemical reactivity of the clean surface (right) than the regions with the boron-induced reconstructions (left) toward disilane. Note the absence of random white protrusions in the left half of the image. Part b shows the enlarged region from the right side of part a, showing SiH3 and SiH2 fragments:
(21a) image dimensions = 380 Å x 250 Å, Vsample = -2.0 V, Itunnel = 0.3 nA;
(21b) image dimensions = 90 Å x 90 Å, Vsample = -2.0 V, Itunnel = 0.3 nA.**


** Figure 21 from Wang, Y.; Hamers, R.J. submitted for publication, 1996.

Figure 22

Image of Si(001) exposed to 0.05 langmuir of B10H14 at 300 K. Image dimensions = 150 Å x 80 Å, Vsample = -4.1 V, Itunnel = 0.3 nA.**


** Figure 22 from Wang, Y.; Shan, J.; Hamers, R.J. J. Phys. Chem. 1996, in press.

Figure 23

Large-scale STM image of a Si(001) surface dosed with ~0.2 langmuir of TMG, showing Ga strings and dimethylgallium (DMG) fragment. Dimension = 265 Å x 300 Å, Vsample = -2.4 V, Itunnel = 0.3 nA.**


** Figure 23 from Bronikowski, M.J.; Hamers, R.J. Surf. Sci. 1995, in press.

Figure 24

STM images of a Si(001) surface dosed with 0.2 langmuir of TMG and then heated to 425 K for 2 min, showing "CH3" and "Ga2 features:
(24a) image dimensions = 123 Å x 123 Å, Vsample = -2.4 V, Itunnel = 0.3 nA;
(21b)high-resolution STM image, showing individual CH3 fragment. Image dimensions = 25 Å x 25 Å, Vsample = -2.4 V, Itunnel = 0.3 nA.**

** Figure 24 from Bronikowski, M.J.; Hamers, R.J. Surf. Sci. 1995, in press.

Figure 25

High-resolution STM image of a Si(001) surface dosed with 0.3 langmuir methyl chloride and then heated to 425 K for 2 min, showing "CH3", Cl2", and "I" features. Area = 90 Å x 75 Å, Vsample = -2.2 V, Itunnel = 0.3 nA.**


** Figure 25 from Bronikowski, M.J.; Hamers, R.J. J. Vac. Sci. Technol. A 1995, 13, 777.

Last updated January 30, 1998