Pretty much every phone camera will experience that grain when taking photos at night. Pretty much the only exceptions would be the Lumia 920 and Nokia 808. But then again, that's why the led flash is put there. I would just diffuse it with wax paper or something so it isn't so harsh.
Samsung has tried to add some software improvements into their 4.1.2 update to make low light shots look better. But it just makes the photo really purple.