Field effect transistor using oxide film for channel and method of manufacturing the same

1. A field effect transistor, comprising an amorphous oxide film as a semiconductor layer,

wherein the amorphous oxide film includes a channel part, a source part, and a drain part, and

wherein a hydrogen concentration of at least one of the source part and the drain part is equal to or larger than 10 17 /cm 3 , and a concentration of one of hydrogen and deuterium in the source part and the drain part is larger than a concentration of one of hydrogen and deuterium in the channel part.

2. A field effect transistor according to claim 1 , wherein the source part and the drain part are disposed in self-alignment with a gate electrode, and have a coplanar structure.

3. A field effect transistor according to claim 1 , wherein a resistivity of at least one of the source part and the drain part is 1/10 or less of a resistivity of the channel part.

4. A field effect transistor according to claim 1 , wherein the oxide film is formed of an amorphous oxide represented by:

[(Sn 1-x M4 x )O 2 ]a .[(In 1-y M3 y ) 2 O 3 ]b .[(Zn 1-z M2 z O)] c,

where 0≦x≦1; 0≦y≦1; 0≦z≦1; 0≦a≦1, 0≦b≦1, 0≦c≦1, and a+b+c=1; M4 is a group VI element selected from a group that includes Si, Ge, and Zr smaller in atomic number than Sn; M3 is Lu or a group III element selected from a group that includes B, Al, Ga, and Y smaller in atomic number than In; and M2 is a group II element selected from a group that includes Mg and Ca smaller in atomic number than Zn.

5. A field effect transistor according to claim 1 , wherein

the field effect transistor is incorporated in a display device with a display element that includes an electrode, and

one of a source part and a drain part of the field effect transistor is electrically connected with the electrode of the display device.

6. A field effect transistor according to claim 5 ,

wherein the display element is one of a plurality of display elements, and the field effect transistor is one of a plurality of field effect transistors, and

wherein the plurality of display elements and the plurality of field effect transistors are two-dimensionally arranged on a substrate.

7. A field effect transistor according to claim 1 , wherein a hydrogen concentration of at least one of the source part and the drain part is equal to or larger than 10 19 /cm 3 .

8. A field effect transistor comprising:

an amorphous oxide semiconductor layer including a channel region;

a gate electrode;

a gate insulator;

a drain electrode; and

a source electrode,

wherein the amorphous oxide semiconductor layer further includes a pair of doped regions adjacent to the source electrode or the drain electrode, each of the doped regions including at least one of hydrogen and deuterium, and

wherein a hydrogen concentration of at least one of the source electrode and the drain electrode is equal to or larger than 10 17 /cm 3 and a concentration of one of hydrogen and deuterium in the doped regions is larger than a concentration of one of hydrogen and deuterium in the channel region.

9. A field effect transistor according to claim 8 , wherein a resistivity of at least one of the source electrode and the drain electrode is equal to or smaller than 1/10 of a resistivity of the channel region.

10. A field effect transistor according to claim 8 , wherein a hydrogen concentration of at least one of the source electrode and the drain electrode is equal to or larger than 10 19 /cm 3 .