Improved Electrical and Optical Properties of IGZO Transparent Conductive Oxide Due to Microwave Treatment: Application to Silicon Solar Cells

The electrical and optical properties of IGZO-based transparent conductive oxide (TCO), fabricated by reactive-sputtering, are optimized using post microwave treatment (MWT), not rapid temperature annealing (RTA), for silicon solar cell. Compared to the sheet resistance and transmittance of IGZO-based TCO after RTA and MWT, we observed a transmittance of over 75 % in the visible and near ultraviolet range of 370-1,200 nm in common, while the lower sheet resistance of 15 Ω/was obtained, which was 3.5 times lower than that of the RTA sample, which resulted in higher current density in IGZO-based TCO after MWT. On the basis of trap density analysis, it is confirmed that the oxygen vacancy within IGZO-based TCO increased as process and power in MWT, which is the reason for the increase in conductivity. Furthermore, short circuit current density (Jsc) was compared to confirm the applicability in the solar cell, which is one of the fields that IGZO mainly uses as a TCO. Jsc of the IGZO based solar cell annealed in MWT at 400W for 60 s was 19.8 mA/cm2.