Method for manufacturing oxide
Provided is a method for manufacturing an oxide with a novel crystal structure, an oxide with high crystallinity, or an oxide with low impurity concentration by a sputtering method. The method comprises the steps of cleaving pellets and aggregates of atoms from a sputtering target containing indium, an element M (aluminum, gallium, yttrium, or tin), and zinc, depositing the pellets and the aggregates of atoms on a substrate, and then filling a gap between the pellets by the aggregates of atoms with lateral growths.
1. A method for manufacturing an oxide, comprising:
supplying a sputtering gas containing at least one of oxygen and a rare gas to a deposition chamber;
giving a potential difference between a target and a substrate to generate plasma containing an ion of the sputtering gas in the vicinity of the target and to accelerate the ion of the sputtering gas toward the target,
wherein the target comprises indium, zinc, an element M, and oxygen,
wherein the element M is one of aluminum, gallium, yttrium, and tin,
wherein the target comprises a region with a polycrystalline structure, and
wherein the target comprises a cleavage plane;
making the accelerated ion of the sputtering gas collide with the target, so that bond cut occurs from an end portion of the cleavage plane, wherein the bond cut is promoted when a charge from the plasma is received;
separating a plurality of crystalline flat-plate-like particles of a compound containing a plurality of elements, atoms contained in the target, and aggregates of the atoms contained in the target from the target by the collision of the accelerated ion, wherein the plurality of crystalline flat-plate-like particles receive negative charges from oxygen ions and have their surfaces negatively charged while flying in the plasma;
depositing one of the plurality of crystalline flat-plate-like particles over the substrate with its flat plane facing the substrate;
depositing another one of the plurality of crystalline flat-plate-like particles over a region apart from the one of the plurality of crystalline flat-plate-like particles over the substrate while repelling the one of the plurality of crystalline flat-plate-like particles;
depositing the atoms and the aggregates of the atoms in a gap between the one of the plurality of crystalline flat-plate-like particles and the another one of the plurality of crystalline flat-plate-like particles; and
filling the gap between the one of the plurality of crystalline flat-plate-like particles and the another one of the plurality of crystalline flat-plate-like particles with the atoms and the aggregates of the atoms that cause a lateral growth.
2. The method according to claim 1 , wherein a direction of an a-axis of the one of the plurality of crystalline flat-plate-like particles over the substrate is different from a direction of an a-axis of the another one of the plurality of crystalline flat-plate-like particles over the substrate.
3. The method according to claim 1 , wherein the oxide is formed over a surface of an amorphous structure.
4. A method for manufacturing an oxide, comprising:
cleaving a first pellet, a second pellet, and aggregates of atoms from a sputtering target, the sputtering target comprising indium, zinc, an element M, and oxygen, and the sputtering target including a region with a polycrystalline structure;
depositing the first pellet over a substrate with its flat plane facing the substrate;
depositing the second pellet apart from the first pellet over the substrate with repelling the first pellet;
depositing the aggregates of atoms in a gap between the first and second pellets; and
filling the gap by the aggregates of atoms with lateral growths.
5. The method according to claim 4 , wherein the element M is aluminum, gallium, yttrium, or tin.
6. The method according to claim 4 , wherein the cleaving is performed by making accelerated ions of a sputtering gas collide with an end portion of a cleavage plane in the sputtering target.
7. The method according to claim 6 , wherein the sputtering gas contains oxygen and a rare gas.
8. The method according to claim 4 , wherein surfaces of the first and second pellets are negatively charged when the first and second pellets are cleaved from the sputtering target.
9. The method according to claim 4 , wherein a direction of an a-axis of the first pellet over the substrate is different from that of the second pellet over the substrate.
10. The method according to claim 4 , wherein the oxide is formed over a surface of an amorphous structure.