Thin film semiconductor device
AssigneeHitachi, Ltd.
InventorsShinya Yamaguchi, Mutsuko Hatano, Mitsuharu Tai, Sedng-Kee Park, Takeo Shiba
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Abstract
A thin film semiconductor device which includes an insulating substrate, a semiconductor polycrystal thin film formed over the substrate and a transistor with the thin film as a channel. The polycrystal includes a plurality of crystal grains, with grain boundaries between the crystal grains being recessed. The grain boundaries with the recessed surfaces are the most predominant of all grain boundaries within the channel. With this structure, the polycrystal can be a low temperature polycrystal that can be formed at a temperature of 150° C. or less, thereby achieving a low-cost device with high carrier mobility.
Claims23
A thin film semiconductor device comprising an insulating substrate, a semiconductor thin film formed to have a lower surface thereof over the insulating substrate, and a transistor with the semiconductor thin film as a channel thereof, wherein
- the semiconductor thin film comprises a polycrystal where a plurality of narrow, rectangular crystal grains are arranged;
- an upper surface of the polycrystal is recessed at grain boundaries between the plurality of narrow rectangular crystal grains thereof in particular;
- and
- the grain boundaries with the recessed surfaces are most predominant of all grain boundaries within the channel.
A thin film semiconductor device comprising an insulating substrate, a semiconductor thin film formed to have a lower surface thereof over the insulating substrate, and a transistor with a semiconductor thin film as a channel thereof, wherein
- a semiconductor thin film comprises a polycrystal where a plurality of crystal grains are arranged;
- an upper surface of the polycrystal is recessed at grain boundaries between the plurality of crystal grains thereof in particular;
- and
- the grain boundaries with the recessed surfaces are most predominant of all grain boundaries within the channel.
A thin film semiconductor device comprising an insulating substrate, a semiconductor thin film formed to have a lower surface thereof over the insulating substrate, and a transistor with the semiconductor thin film as a channel thereof, wherein
- the semiconductor thin film comprises a polycrystal where a plurality of narrow, rectangular crystal grains are arranged;
- an upper surface of the polycrystal is recessed at grain boundaries between the plurality of narrow rectangular crystal grains thereof in particular;
- and
- the grain boundaries with the recessed surfaces are most predominant of all grain boundaries within the channel, and
- wherein a most predominant crystal surface orientation of the rectangular crystal grains in a direction perpendicular to the substrate is a <110> orientation.
A thin film semiconductor device comprising an insulating substrate, a semiconductor thin film formed to have a lower surface thereof over the insulating substrate, and a transistor with the semiconductor thin film as a channel thereof, wherein
- the semiconductor thin film comprises a polycrystal where a plurality of crystal grains are arranged;
- upper surface of the polycrystal is recessed at grain boundaries between the plurality of crystal grains thereof in particular;
- and
- the grain boundaries with the recessed surfaces are most predominant of all grain boundaries within the channel, and
- wherein a most predominant crystal surface orientation of the crystal grains in a direction perpendicular to the substrate is a <110> orientation.
Dependencies are inferred from the claim text.