Home – Home – Jornals – Chemistry for Sustainable Development 2000 number 1-2

As terahertz frequency devices, 100 Å scale ideal static induction transistor (ISIT) was fabricated with GaAs molecular layer epitaxy (MLE). The ISIT is estimated as electron transit time of 2⋅l0^–14 s. In order to control the doping MLE at a sidewall in the fabrication process, the doping characteristics on each crystallographic orientation surfaces of GaAs substrate have been studied. In addition, the lateral growth rate on nanometre height step has been estimated by using table method. MLE of Si and SiO₂ layers were also tried with investi- gating the surface reaction by using in situ mass spectroscopy. For Si growth, temperature modulation (TM) method was performed using Si₂H₆ as source gas. SiO₂ thin layer was successfully deposited in Si MLE sys- tem by simultaneous supply of Si₂H₆ and active oxygen from helicon plasma source. Small temperature and pressure dependence of the deposition rate about 0.2–0.3 nm/min is useful for atomic and molecular level controlled process.