We have developed high power integrated thermoelectric generators (?TEGs). These ?TEGs are CMOS compatible, i.e. based on polycristalline SiGe materials. These ?TEGs have been processed directly on a silicon interposer. Even if poly-SiGe exhibits low thermoelectric performances at room temperature, the specific design and proposed architecture enable ?TEGs to deliver up to 680 ?W for a temperature difference at 15.5 K. To reach such high power, an original 2.5D structure has been developed and ?channels technology has been associated, below the ?TEG, to dissipate heat coming from the hot side. ?TEGs have been tested in real environment, located below a hot test chip. Such ?TEG performances overtake those from similar state-of-the-art CMOS compatible devices, and pave the way for a potential use in different applications such as sensors power supply or battery charger. © 2022 Elsevier Ltd