Atmospheric pressure dielectric barrier discharge (DBD) for post-annealing of aluminum doped zinc oxide (AZO) films

Aluminum-doped zinc oxide (AZO) is a material that can have high electrical conductivity while being highly transparent at the same time. It has been used in many applications such as displays, mobile devices and solar cells. Currently AZO films are considered as attractive alternatives to materials such as indium–tin oxide (ITO) due to its much cheaper cost and comparable high electrical conductivity. A process of depositing AZO film by dual DC magnetron and RF enhancement system has been developed. Film thicknesses were measured to be at about 200nm by a stylus contact profilometer and transparency of greater than 90% in the visible range was measured with spectrophotometry methods. Film conductivities were on the order of 10−3Ω-cm using the four-point probe method. By using a dielectric barrier discharge operating at atmospheric pressure, the conductivity of film can be further lowered. A 300mm×60mm line source operating at a nitrogen flow of ~250L/min was used and ~0.4L/min hydrogen gas was also introduced into the discharge system to create hydrogen radicals for surface modification. A 10%–15% decrease in electrical resistance was observed with no changes in the optical properties of the AZO films.