Low-temperature homoepitaxial film growth of Si by reactive ion beam deposition

Abstract

Homoepitaxial film growth maintaining primary surface structures of Si substrates was investigated by using the reactive ion beam deposition method proposed recently. This method uses ionized species of reactive SiH4 gas controlled in the low-energy region of less than 500 eV. At 100–150 eV, homoepitaxial film growth on Si(111) and Si(100) maintaining their primary 7×7 and two-domain 2×1 surface structures, respectively, can be achieved at the low temperatures of 650 and 600 °C, respectively. In addition, oxygen impurities on substrate surfaces, due to imperfect substrate cleaning and recontamination caused by residual gases in a growth chamber before film growth, were successfully reduced at 600 °C by irradiating the 100-eV controlled ionized species onto them.

Low temperature epitaxial silicon film growth using high vacuum electron-cyclotron-resonance plasma deposition

“…3 Most of the current techniques for growing epitaxial silicon films below 600°C require UHV conditions due to their extremely low growth rates ͑Ͻ1 Å/s͒. 2,[5][6][7][8] In contrast, the enhanced surface mobility of radicals due to ion bombardment in the ECR plasma allows typical growth rates of more than 3.5 Å/s to be achieved. The growth rate in this type of system is very sensitive to the process conditions, especially the pressure, and silane to hydrogen ratio.…”

“…To achieve such a low temperature growth, various techniques, such as ultrahigh vacuum chemical vapor deposition ͑UHV-CVD͒, 1,2 very low pressure CVD, 3 plasma enhanced CVD, 4 and low pressure UHV electron-cyclotron-resonance ͑ECR͒ CVD [5][6][7][8] have been used. The advantages of ECR-CVD are the low particulate production in the reactor, enhanced growth rate at low temperatures, and the ability to control plasma potentials, and hence ion bombardment of the substrate, during growth.…”

1.5 - nm -thick silicon oxide gate films grown at 150°C using modified reactive ion beam deposition with pyrolytic-gas passivation

“…These measurements were performed by ellipsometry with the index group of refraction of the oxide films fixed to the mean value of 1.465, and the accuracy of the thicknesses derived from ellipsometry was estimated to be within ±0.05 nm from the geometric arrangement of our optical system and the errors in optical constants. Although the RIBC-cleaned wafer surface exhibits the so-called Si͑100͒-2 ϫ 2 superstructure consisting of Si͑100͒-2 ϫ 1 and −1 ϫ 2 superstructures and produces a 2 ϫ 1-and 1 ϫ 2-domain terrace with steps of one interatomic distance, 38,44 the influence of the steps cannot be observed within the area of the present image. 76 Figure 2 shows a HR-TEM image with 4 ϫ 10 6 magnification of the 1.5-nm-thick RIBD-with-PGP-grown silicon oxide films on n-type Si͑100͒ wafers covered with in situ P-doped RIBD-grown polycrystalline Si films.…”

“…5, 16 However, its effects can be confirmed only at a humidity of less than 1 ppb. 5,9,24 In this work, to extend these PGP effects to lowtemperature silicon oxide gate film growth, the previously proposed reactive ion beam deposition ͑RIBD͒ method [35][36][37][38][39][40][41] was modified and applied to the low-temperature growth while maintaining the high reliability level in a common large-scale integration device process. That is, instead of H passivation of all silicon dangling bonds in the oxide films and near their interfaces, N passivation against parts of the residual H-related single bonds aggressively proceeds in situ by the thermally activated NO 2 and N 2 generated from the pyrolytic N 2 O.…”

“…That is, instead of H passivation of all silicon dangling bonds in the oxide films and near their interfaces, N passivation against parts of the residual H-related single bonds aggressively proceeds in situ by the thermally activated NO 2 and N 2 generated from the pyrolytic N 2 O. Using the RIBD method, polycrystalline Si ͑polysilicon͒, 35 highly preferred polysilicon on amorphous insulators, 36,37 homoepitaxial Si with 7 ϫ 7 and 2 ϫ 2 surface superstructures, 38 heteroepitaxial Sion-sapphire without microtwins, 39,40 and heteroepitaxial 3C-SiC-on-Si ͑Ref. 5 Since the additional ef-fects of F passivation have been confirmed, [25][26][27][28] it is believed that F passivation effectively contributes to compensate the inconsistent-state bonding sites near the interface that remain after N passivation.…”