Carrier transport, structure and orientation in polycrystalline silicon on glass

Growth, structure, and transport properties of thin (>10 nm) n-type microcrystalline silicon prepared on silicon oxide and its application to single-electron transistor

“…As Nakahata et al report, Hall mobility has a good correlation with the lateral grain size measured by SEM and the lateral growth in preferentially oriented poly-Si occurs together with a decrease in orientation fluctuation. 12,22 Their results imply that the chemical bonding structure at the growth surface affects the structure of the subsequently grown film. In contrast, it is thought that the growth of the randomly oriented c-Si:H is not affected by the growth surface structure under the deposition condition used because the perpendicular grain size of the c-Si:H measured by XRD (D 220 ) is much smaller than the film thickness and also smaller than those measured in the ͑220͒ or ͑400͒ preferentially oriented poly-Si.…”

“…We note that quantum confinement effects in such small grain size silicon-based material have been observed as a blueshift in photoluminescence. 17 Poly-/ c-Si:H prepared at low temperatures on glass can have an inhomogeneous structure and structural and transport properties such as grain size, crystalline fraction, orientation fluctuation and carrier mobilities can be a strong function of film thickness [18][19][20][21][22][23] In addition, the film structure and transport properties can be changed by doping. This indicates that it is necessary to study film microstructure and transport properties at a thickness and doping concentration that is used in a specific device application.…”

Fluorine‐Mediated Crystallization of Silicon in Plasma‐Enhanced CVD

“…Figure 1 shows the crystal volume fraction evaluated by Raman spectroscopy in the temperature range 350 À 450 8C. The crystallinity of the films obtained by the present study (^) is compared with previous studies of crystalline Si deposition by PECVD with SiH 4 , () [2][3][4] and SiF 4 (^), [5][6][7] where H 2 or H 2 þ He were used as diluents, as shown in Figure 2. It is clear that crystal growth based on dilution in H 2 was achieved at temperatures lower than 400 8C under various conditions, however the crystallinity of films grown above 400 8C degraded strongly, as shown in the literature.…”

“…To date, various material systems, such as SiH 4 þ H 2 , [2][3][4] SiH 4 þ SiF 4 þ H 2 , [5] SiF 4 þ H 2 , [6] and SiH 4 þ SiF 4 [7] have been investigated for the deposition of mc-Si:H. Most studies have emphasized that atomic hydrogen (H) plays a key role in crystal growth, even in systems where a fluorinated source gas, such as SiF 4 , is used. In fact, it is well known that the film crystallinity is much improved, even at low temperatures, by the addition of H. [2] This contribution has been explained by various models, which include enhanced surface migration of film precursors on growth surfaces that are wellpassivated with H, [8] preferential etching of amorphous tissue by atomic H, [9] and chemical annealing, (i.e., the enhanced structural relaxation of the Si network mediated by reactive atomic H).…”

Addition of SiF4 to standard SiH4+H2 plasma: an effective way to reduce oxygen contamination in μc‐Si:H films

“…On one hand, it was found that depending on the SiF 4 /SiH 4 ratio one can obtain materials with different structure from amorphous to highly crystallized [12]. On the other hand, it was shown that changes in the preferential orientation of grains of highly crystallized µc-Si:F:H deposited from SiF 4 +H 2 +Ar were followed by significant changes in oxygen content [13]. However, in both cases changes in structure lead to the significant changes in ellipsometric spectra [12,14].…”