High density integrated Point-of-Load (POL) converter is today's industry trend for portable electronic applications. In the past 10 years, Center for Power Electronics Systems (CPES) spent tremendous research efforts in this area and has successfully demonstrated a three-dimension (3D) integration method using magnetic as a substrate to achieve a very high power density at a high current level. CPES not only proposed a series of methods to reduce parasitic inductance of active layer for high frequency operation, but also developed several advanced low profile magnetic structures for 3D integration. This paper gives an overview of CPES's 10-year research efforts on high density 3D integrated POL converters. With CPES's latest technologies, a 20A POL converter with GaN devices was demonstrated with power density as high as 1000W/in 3 , which is a factor of 10 improvements compared to industry products.