Cu—In—Ga—Se quaternary alloy sputtering target
View Patent ↗A quaternary alloy sputtering target composed of copper (Cu), indium (In), gallium (Ga) and selenium (Se), wherein a composition ratio of the respective elements is represented by a formula of Cu x In 1-y Ga y Se a (in the formula, 0.84≦x≦0.98, 0<y≦0.5, a=(1/2)x+3/2), and a structure observed via EPMA is configured only from a Cu(In, Ga)Se 2 phase without any heterogenous phase of Cu 2 Se or Cu(In, Ga) 3 Se 5 . Provided is a CIGS quaternary alloy sputtering target which is subject to hardly any abnormal discharge even when sputtered for a long period, which is free of any heterogenous phase of Cu 2 Se or Cu(In, Ga) 3 Se 5 which causes the deterioration in the conversion efficiency of the film after being sputter-deposited, and which can produce a film having superior in-plane uniformity. Additionally provided is a CIGS quaternary alloy sputtering target having a predetermined bulk resistance and a high density.
1. A Cu—In—Ga—Se quaternary alloy sputtering target consisting of copper, indium, gallium and selenium, wherein the Cu—In—Ga—Se quaternary alloy has a composition expressed by a formula of Cu x In 1-y Ga y Se a , where x, y and a satisfy 0.84≦x≦0.98, 0<y≦0.5, and a=(1/2)x+3/2 respectively, and a sintered structure which, in observation by EPMA, is configured only from a Cu(In, Ga)Se 2 phase without any heterogeneous phase of Cu 2 Se or Cu(In, Ga) 3 Se 5 .
2. The Cu—In—Ga—Se quaternary alloy sputtering target according to claim 1 , wherein a density of the target is 5.5 g/cm 3 or more.
3. The Cu—In—Ga—Se quaternary alloy sputtering target according to claim 2 , wherein, in the structure observed via EPMA, an average diameter of an In, Ga agglomeration phase is 100 μm or less.
4. The Cu—In—Ga—Se quaternary alloy sputtering target according to claim 3 , wherein an oxygen concentration is 200 wtppm or less.
5. The Cu—In—Ga—Se quaternary alloy sputtering target according to claim 1 , wherein, in the structure observed via EPMA, an average diameter of an In, Ga agglomeration phase is 100 μm or less.
6. The Cu—In—Ga—Se quaternary alloy sputtering target according to claim 1 , wherein an oxygen concentration is 200 wtppm or less.
7. The Cu—In—Ga—Se quaternary alloy sputtering target according to claim 1 , wherein the value of y in the formula Cu x In 1-y Ga y Se a equals 0.2.
8. The Cu—In—Ga—Se quaternary alloy sputtering target according to claim 1 , wherein the value of y in the formula Cu x In 1-y Ga y Se a satisfies 0.2≦y≦0.5.