In this work, new 3D vertical RRAM device with silicon CMOS compatibility and the possible fabrication process are presented. RRAM devices based on Ni/Si3N4/p+-Si stack which are applicable in our proposed 3D vertical RRAM structure were fabricated in order to reveal the effects of switching layer thickness and compliant current on resistive switching parameters. Forming-less behavior can be easily achieved by controlling thickness of the Si3N4 layer. It is found that the high- and low-resistance state can be effectively modulated by the film thickness and compliance current, respectively.