Stable amorphous metal oxide semiconductor
A thin film semiconductor device has a semiconductor layer including a mixture of an amorphous semiconductor ionic metal oxide and an amorphous insulating covalent metal oxide. A pair of terminals is positioned in communication with the semiconductor layer and define a conductive channel, and a gate terminal is positioned in communication with the conductive channel and further positioned to control conduction of the channel. The invention further includes a method of depositing the mixture including using nitrogen during the deposition process to control the carrier concentration in the resulting semiconductor layer.
1. A method of forming a layer of stable amorphous metal oxide material for use as a semiconductor in semiconductor devices, the method comprising the steps of:
providing an amorphous semiconductor ionic metal oxide material;
providing an amorphous insulating covalent metal oxide material;
mixing the amorphous insulating covalent metal oxide material with the amorphous semiconductor ionic metal oxide material in a predetermined ratio forming a continuous network of the amorphous semiconductor ionic metal oxide material;
depositing the mixture of the amorphous semiconductor ionic metal oxide and the amorphous insulating covalent metal oxide on a substrate; and
controlling carrier concentration of the mixture using one of oxygen and nitrogen during the deposition.
2. A method as claimed in claim 1 wherein the step of depositing the mixture of amorphous semiconductor ionic metal oxide and amorphous insulating covalent metal oxide includes depositing a mixture with a greater amount of the amorphous semiconductor ionic metal oxide than the amount of amorphous insulating covalent metal oxide.
3. A method as claimed in claim 2 wherein the step of depositing the mixture of amorphous semiconductor ionic metal oxide and amorphous insulating covalent metal oxide includes depositing a mixture with an amount of the amorphous semiconductor ionic metal oxide greater than approximately 17% of the mixture.
4. A method as claimed in claim 2 wherein the step of depositing the mixture of amorphous semiconductor ionic metal oxide and amorphous insulating covalent metal oxide includes depositing a mixture with an amount of amorphous insulating covalent metal oxide sufficient to prevent the amorphous semiconductor ionic metal oxide from becoming poly crystalline at high temperatures.
5. A method as claimed in claim 1 wherein the step of depositing the mixture of amorphous semiconductor ionic metal oxide and amorphous insulating covalent metal oxide includes depositing a mixture with an amount of amorphous insulating covalent metal oxide sufficient to prevent the amorphous semiconductor ionic metal oxide from becoming poly crystalline at temperatures in a range of approximately 250° C. to approximately 700° C.
6. A method as claimed in claim 1 wherein the step of depositing the mixture of amorphous semiconductor ionic metal oxide and amorphous insulating covalent metal oxide includes depositing a mixture with an amount of amorphous insulating covalent metal oxide sufficiently small to allow a continuous network of the amorphous semiconductor ionic metal oxide.
7. A method as claimed in claim 4 wherein the step of depositing the mixture of amorphous semiconductor ionic metal oxide and amorphous insulating covalent metal oxide includes depositing a mixture with an amount of amorphous insulating covalent metal oxide greater than approximately 5% of the mixture.
8. A method as claimed in claim 1 wherein the step of depositing the mixture of amorphous semiconductor ionic metal oxide and amorphous insulating covalent metal oxide includes depositing a mixture in which the amorphous semiconductor ionic metal oxide includes one of zinc oxide, indium oxide, tin oxide, and combinations thereof.
9. A method as claimed in claim 1 wherein the step of depositing the mixture of amorphous semiconductor ionic metal oxide and amorphous insulating covalent metal oxide includes depositing a mixture in which the amorphous insulating covalent metal oxide includes one of aluminum oxide, silicon oxide, magnesium oxide, beryllium oxide, boron oxide, and combinations thereof.
10. A method as claimed in claim 1 wherein the step of controlling carrier concentration of the mixture includes using nitrogen during the deposition.
11. A method of forming a layer of stable amorphous metal oxide material for use as a semiconductor in semiconductor devices, the method comprising the steps of:
providing a relatively unstable amorphous semiconductor ionic metal oxide including one of zinc oxide, indium oxide, tin oxide, and combinations thereof;
providing a stable amorphous insulating covalent metal oxide including one of aluminum oxide, silicon oxide, magnesium oxide, beryllium oxide, boron oxide, and combinations thereof;
mixing the amorphous insulating covalent metal oxide material with the amorphous semiconductor ionic metal oxide material in a predetermined ratio sufficient to allow a continuous network of the amorphous semiconductor ionic metal oxide and to prevent the amorphous semiconductor ionic metal oxide from becoming poly crystalline at temperatures in a range of approximately 250° C. to approximately 700° C.;
depositing the mixture of the amorphous semiconductor ionic metal oxide and the amorphous insulating covalent metal oxide on a substrate; and
controlling carrier concentration of the mixture using one of oxygen and nitrogen during the deposition.