Electro-optical device and semiconductor circuit
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsHisashi Ohtani, Jun Koyama, Shunpei Yamazaki
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Abstract
A high performance circuit is formed by using a TFT with less fluctuation in characteristics, and a semiconductor device including such a circuit is formed. When the TFT is formed, first, a base film and a semiconductor film are continuously formed on a quartz substrate without exposing to the air. After the semiconductor film is crystallized by using a catalytic element, the catalytic element is removed. In the TFT formed in such a process, fluctuation in electrical characteristics such as a threshold voltage and a subthreshold coefficient is extremely small. Thus, it is possible to form a circuit, such as a differential amplifier circuit, which is apt to receive an influence of characteristic fluctuation of a TFT.
Claims30
A semiconductor device comprising a plurality of thin-film transistors formed over a same substrate, said thin-film transistors comprising:
- a crystalline semiconductor film having a {110} plane orientation in channel formation regions of said thin-film transistors,
- wherein 90% or more of crystal lattices have continuity at any crystal grain boundaries in said channel formation regions, and
- wherein a standard deviation is 0.1 V or less when a collective of threshold voltages exhibited by the plurality of the respective thin-film transistors is made a population.
A semiconductor device comprising a plurality of thin-film transistors formed over a same substrate, said thin-film transistors comprising:
- a crystalline semiconductor film having a {110} plane orientation in channel formation regions of said thin-film transistors,
- wherein a standard deviation is 0.1 V or less when a collective of threshold voltages exhibited by the plurality of the respective thin-film transistors is made a population.
A semiconductor device comprising a plurality of thin-film transistors formed over a same substrate, said thin-film transistors comprising:
- a crystalline semiconductor film having a {110} plane orientation in channel formation regions of said thin-film transistors,
- wherein said {110} plane orientation is observed by an electron beam diffraction pattern when an electron beam is vertically irradiated to said channel formation regions, and
- wherein a standard deviation is 0.1 V or less when a collective of threshold voltages exhibited by the plurality of the respective thin-film transistors is made a population.
A semiconductor device comprising a plurality of thin-film transistors formed over a same substrate, said thin-film transistors comprising:
- a crystalline semiconductor film having a {110} plane orientation in channel formation regions of said thin-film transistors,
- wherein 90% or more of crystal lattices have continuity at any crystal grain boundaries in said channel formation regions, and
- wherein a standard deviation is 10 mV/dec or less when a collective of subthreshold coefficients exhibited by the plurality of the respective thin-film transistors is made a population.
A semiconductor device comprising a plurality of thin-film transistors formed over a same substrate, said thin-film transistors comprising:
- a crystalline semiconductor film having a {110} plane orientation in channel formation regions of said thin-film transistors,
- wherein a standard deviation is 10 mV/dec or less when a collective of subthreshold coefficients exhibited by the plurality of the respective thin-film transistors is made a population.
A semiconductor device comprising a plurality of thin-film transistors formed over a same substrate, said thin-film transistors comprising:
- a crystalline semiconductor film having a {110} plane orientation in channel formation regions of said thin-film transistors,
- wherein said {110} plane orientation is observed by an electron beam diffraction pattern when an electron beam is vertically irradiated to said channel formation regions, and
- wherein a standard deviation is 10 mV/dec or less when a collective of subthreshold coefficients exhibited by the plurality of the respective thin-film transistors is made a population.
Dependencies are inferred from the claim text.