A method of forming an Integrated Circuit (IC) chip, the IC chip and an on-chip synaptic crossbar memory array. Chip devices are formed on a surface of a semiconductor wafer. A connective layer is formed above the chip devices. A bottom electrode layer is formed on the connective layer. A neuromorphic synapse layer is formed above the bottom electrode layer with each synapse on a bottom electrode. Upper electrodes are formed above the synapses and orthogonal to bottom electrode lines. Each synapse being beneath an upper electrode where the upper electrode crosses a bottom electrode. Upper electrodes are refractory metal and the bottom electrodes are copper, or vice versa.