I've solved the problem by putting a 100pF capacitor (the only one I had here, but with the xoscope it seemed to work very well) between the gate of the mosfet and ground. It seems that this way I've provided a low impedance path to the high frequencies of the spike when turning off the gate driving. Maybe the manual wiring to ground had a higher impedance than if it has the ground layer as it was supposed to have.

Thank you all for your time.
ale

I've solved the problem by putting a 100nF capacitor (the only one I had here, but with the xoscope it seemed to work very well) between the gate of the mosfet and ground. It seems that this way I've provided a low impedance path to the high frequencies of the spike when turning off the gate driving. Maybe the manual wiring to ground had a higher impedance than if it has the ground layer as it was supposed to have.

Thank you all for your time.
ale