Semiconductor device having a polycrystalline silicon film with crystal grains having a uniform orientation
AssigneeHitachi, Ltd.
InventorsHideo Miura, Shunji Moribe, Hisayuki Kato, Atsuyoshi Koike, Shuji Ikeda, Asao Nishimura
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Abstract
A semiconductor device containing a polycrystalline silicon thin film wherein crystal grains of the silicon thin film have mainly a columnar structure and a crystal orientation of individual crystal grains is almost in a uniform direction can be produced by depositing a non-impurity-doped silicon thin film or an impurity layer on an interface of underlying film, followed by deposition of impurity-doped silicon thin film, if necessary, followed by heat treatment for polycrystallization.
Claims19
A semiconductor device comprising a semiconductor substrate, an underlying film formed thereon and a silicon thin film, as a single body of a plurality of crystal grains of silicon, doped with an impurity selected from a group consisting of group III and V elements and formed on the underlying film, the crystal grains of said silicon thin film as a single body having mainly a columnar structure grown from an interface of the underlying film to a surface of the silicon thin film, and a crystal orientation on film surfaces of individual crystal grains of said silicon thin film as a single body being in an almost uniform direction, wherein an impurity concentration of the silicon thin film near an interface between the underlying film and the silicon thin film is sufficiently low or sufficiently high, compared with an average impurity concentration in the silicon thin film, such that the crystal orientation is in the almost uniform direction.
A metal-oxide-silicon field-effect transistor comprising a silicon single crystal substrate, a gate oxide film and a gate electrode, formed on the gate oxide film, said gate electrode being made of a silicon thin film, as a single body of a plurality of crystal grains of silicon, doped with an impurity selected from a group consisting of group III and V elements, said silicon thin film being deposited on the gate oxide film, crystal grains of said silicon thin film having mainly a columnar structure grown from an interface of the gate oxide film to a surface of the silicon thin film, a crystal orientation of film surfaces of individual crystal grains of said silicon thin film as a single body being in an almost uniform direction, wherein an impurity concentration of the silicon thin film near an interface between the underlying film and the silicon thin film is sufficiently low or sufficiently high, compared with an average impurity concentration in the silicon thin film, such that the crystal orientation is in the almost uniform direction.
Dependencies are inferred from the claim text.