Are Infiniti FX 35 brake pads supposed to be organic?

I just (2 months ago) replaced the brake pads on my 2003 Infiniti FX35, with semi-metallic pads. The car is making a screeching noise. A friend said it could be because the car may need organic pads, and the semi-metallic are grinding on the rotor. What are required for this car, organic or metallic?