Evolution of the Classical Functional Integration Towards a 3D Heterogeneous Functional Integration

This paper presents a brief overview of the monolithic integration in the field of power electronics. Emphasis is mainly put on the functional integration concept. The role that this mode of integration, according to its classical definition, played to enable the monolithic integration of the power device with auxiliary elements (mainly protections and supply) for the realization of new functions dedicated for medium power applications is highlighted. At that end, some of the recent realizations are described in order to showcase some of the potentialities of this mode of integration. Furthermore, to extend further the classical integration towards a 3D "heterogeneous" functional integration, an example that highlights the improvements that should be achieved at the device\´s level as well as at the device\´s environment level, for the development of new power integrated functions for AC applications, is discussed. The last part deals with the technology process evolution for the realization of the active devices as well as the passive elements. In this part, a flexible technological process and its importance in the development of more complex functions, implemented in 3D within the silicon die volume and at the surface, is described in more detail.