Effects of deposition condition on the ionic conductivity and structure of amorphous lithium phosphorus oxynitrate thin film

For the amorphous thin film LIPON electrolytes deposited by sputtering from a Li sub 3 PO sub 4 target, the ionic conductivity of the film increased linearly with rf power up to 5 W/cm exp 2 without a significant influence of nitrogen pressure between 0.7-2.7 Pa. With the incorporation of nitrogen into a phosphate glass structure during sputtering, the number of P-N < sub P exp P and P=N-P bonds increased at the expense of P-O-P bonds, leading to a transformation of an oxgyen bridging structure to a nitrogen cross linking (-N < ) and a linear linking (-N=) structure. This structural change appears to increase the mobility of Li exp + in amorphous LIPON films thereby increasing the ionic conductivity. The maximum ionic conductivity, 1.0x10 exp -6 Omega exp -1 cm exp -1 , of LIPON film is obtained when the bonding raio of P-O-P/P=O is at a minimum and the nitrogen content is at a maximum. This condition was achieved for films deposited by sputtering either with the target of Li sub 3 PO sub 4 at rf power of 5 W/cm exp 2 or with the mixture target of Li sub 3 PO sub 4 +Li sub 3 N at 3 W /cm exp 2 .