I would use a MOSFET gate driver with such a large MOSFET. place the gatedriver close to the MOSFET, use 0.1uF decoupling capacitor across the driver power pins and connect GND for the driver as near the Source pin as possible to reduce the inductance in the trace. (the MOSFET current will cause a voltage drop in the trace connected to Source. this is probably what you are seeing on the scope.) a 1 to 10ohm resistor between driver output and Gate can be used to control the switching speed of the MOSFET. the gate resistor will increase power losses in the MOSFET during switching.