Semiconductor thin film and semiconductor device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsShunpei Yamazaki, Hisashi Ohtani, Toru Mitsuki, Akiharu Miyanaga, Yasushi Ogata
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Abstract
After an amorphous semiconductor thin film is crystallized by utilizing a catalyst element, the catalyst element is removed by performing a heat treatment in an atmosphere containing a halogen element. A resulting crystalline semiconductor thin film exhibits {110} orientation. Since individual crystal grains have approximately equal orientation, the crystalline semiconductor thin film has substantially no grain boundaries and has such crystallinity as to be considered a single crystal or considered so substantially.
Claims17
A semiconductor thin film comprising a collected body of a plurality of rod-like or flat-rod-like crystals each comprising silicon as a main component, wherein a main orientation plane substantially coincides with a {110} plane,
- wherein a concentration, in the semiconductor thin film, of each of carbon and nitrogen is 5.times.10.sup.17 atoms/cm.sup.3 or less and a concentration of oxygen is 1.times.10.sup.18 atoms/cm.sup.3 or less, respectively, and
- wherein the rod-like or flat-rod-like crystals contact each other while forming rotation angles having absolute values that are within 3.degree..
A semiconductor device comprising a semiconductor film having at least a channel forming region, said semiconductor film comprising a collected body of a plurality of rod-like or flat-rod-like crystals each having silicon as a main component,
- wherein a main orientation plane of the semiconductor thin film substantially coincides with a {110} plane,
- wherein a concentration, in the semiconductor thin film, of each of carbon and nitrogen is 5.times.10.sup.17 atoms/cm.sup.3 or less and a concentration of oxygen is 1.times.10.sup.18 atoms/cm.sup.3 or less, and
- wherein the rod-like or flat-rod-like crystals contact each other while forming rotation angles having absolute values that are within 3.degree..
A semiconductor device comprising a semiconductor thin film having a main orientation plane substantially coinciding with a {110} plane,
- wherein a concentration, in the semiconductor thin film, of each of carbon and nitrogen is 5.times.10.sup.17 atoms/cm.sup.3 or less and a concentration of oxygen is 1.times.10.sup.18 atoms/cm.sup.3 or less, respectively,
- wherein an electron beam diffraction pattern of the semiconductor thin film has particular regularity due to {110} orientation,
- wherein each of diffraction spots of the electron beam diffraction pattern is substantially circular, and
- wherein a ratio of a minor-axis length to a major-axis length of each of the diffraction spots is in a range of 1/1 to 1/1.5.
A semiconductor device comprising a semiconductor thin film comprising a main orientation plane substantially coinciding with a {110} plane,
- wherein a concentration, in the semiconductor thin film, of each of carbon and nitrogen is 5.times.10.sup.17 atoms/cm.sup.3 or less and a concentration of oxygen is 1.times.10.sup.18 atoms/cm.sup.3 or less, respectively,
- wherein an electron beam diffraction pattern of the semiconductor thin film has particular regularity due to {110} orientation,
- wherein each of diffraction spots of the electron beam diffraction pattern has a spread that is on a concentric circle having a center at a central point of an electron beam irradiation area, and
- wherein a tangential line to each of the diffraction spot from the central point of the electron beam irradiation area and a line segment connecting the central point of the electron beam irradiation area and a central point of the diffraction spot form an angle that is within .+-.1.5.degree..
Dependencies are inferred from the claim text.