A study of electronic shorting in IBDA-deposited Lipon films

Because a near term goal of our research is to obtain optimal performance LiCoO2/lithium phosphorus oxynitride (Lipon)/C thin film batteries, and due to the major importance of the electrolyte in any battery, we have recently been attempting to better understand the causes of electronic shorting in our Lipon electrolyte films. After studying the residual and temperature-dependent stress of these films and observing cracking after they had undergone a temperature change from 300°C to room temperature, we adopted a model in which the thermal expansion coefficient mismatch between Lipon and our glass substrates accounted for the cracking and therefore led to the shorting. This model was also supported by evidence that Al films (which had thermal expansion coefficients close to that of Lipon and proved to act as “buffer layers” by preventing cracking of Lipon when glass/Al/Lipon structures were cooled from 300°C to room temperature) were successfully used to produce short-free Al/Lipon/Al devices.