A method of reading a memory device having rows and columns of memory cells formed on a substrate, where each memory cell includes spaced apart first and second regions with a channel region therebetween, a floating gate disposed over a first portion of the channel region, a select gate disposed over a second portion of the channel region, a control gate disposed over the floating gate, and an erase gate disposed over the first region. The method includes placing a small positive voltage on the unselected source lines, and/or a small negative voltage on the unselected word lines, during the read operation to suppress sub-threshold leakage and thereby improve read performance.