Embodiments herein relate to a system in package (SiP). The SiP may have a first layer of one or more first functional components with respective first active sides and first inactive sides opposite the first active sides. The SiP may further include a second layer of one or more second functional components with respective second active sides and second inactive sides opposite the second active sides. In embodiments, one or more of the first active sides are facing and electrically coupled with one or more of the second active sides through a through-mold via or a through-silicon via.