A method of fabricating a microelectronic assembly including a built-in thermoelectric cooler, TEC, and a microelectronic device coupled to the TEC, the method comprising: providing the microelectronic device; fabricating the built-in TEC directly onto the microelectronic device such that there is no mounting material between the built-in TEC and the microelectronic device; wherein fabricating the built-in TEC comprises: initially forming a plurality of first conductive elements (124, 128, 132) of the built-in TEC directly on the microelectronic device; subsequently forming a N-type layer of thermoelectric, TE, material on the plurality of first conductive elements; subsequently forming an electrode pattern in the N-type layer to yield a plurality of N-type electrodes; subsequently depositing an electrical insulator layer between the N-type electrodes and between the first conductive elements; forming an electrode pattern in the electrical insulator layer to define vias therein, said vias exposing a portion of said first conductive elements; forming a plurality of P-type conductivity legs of TE material in the vias defined in the electrical insulator layer; and etching back the P-type conductivity legs to yield a plurality of P-type electrodes; wherein each P-type electrode is electrically coupled to a corresponding one of the first conductive elements, and an N-type electrode and a P-type electrode are coupled to each given one of the first conductive elements together forming a pair of N-type and P-type electrodes; providing a plurality of second conductive elements (122, 126, 130, 134) such that each of the second conductive elements is adapted to allow electrical current to flow in series through respective pairs of N-type and P-type electrodes; and wherein the electrode pattern in the electrical insulator layer corresponds to a pattern of P-type electrodes. providing the microelectronic device; fabricating the built-in TEC directly onto the microelectronic device such that there is no mounting material between the built-in TEC and the microelectronic device; wherein fabricating the built-in TEC comprises: initially forming a plurality of first conductive elements (124, 128, 132) of the built-in TEC directly on the microelectronic device; subsequently forming a N-type layer of thermoelectric, TE, material on the plurality of first conductive elements; subsequently forming an electrode pattern in the N-type layer to yield a plurality of N-type electrodes; subsequently depositing an electrical insulator layer between the N-type electrodes and between the first conductive elements; forming an electrode pattern in the electrical insulator layer to define vias therein, said vias exposing a portion of said first conductive elements; forming a plurality of P-type conductivity legs of TE material in the vias defined in the electrical insulator layer; and etching back the P-type conductivity legs to yield a plurality of P-type electrodes; initially forming a plurality of first conductive elements (124, 128, 132) of the built-in TEC directly on the microelectronic device; subsequently forming a N-type layer of thermoelectric, TE, material on the plurality of first conductive elements; subsequently forming an electrode pattern in the N-type layer to yield a plurality of N-type electrodes; subsequently depositing an electrical insulator layer between the N-type electrodes and between the first conductive elements; forming an electrode pattern in the electrical insulator layer to define vias therein, said vias exposing a portion of said first conductive elements; forming a plurality of P-type conductivity legs of TE material in the vias defined in the electrical insulator layer; and etching back the P-type conductivity legs to yield a plurality of P-type electrodes; wherein each P-type electrode is electrically coupled to a corresponding one of the first conductive elements, and an N-type electrode and a P-type electrode are coupled to each given one of the first conductive elements together forming a pair of N-type and P-type electrodes; providing a plurality of second conductive elements (122, 126, 130, 134) such that each of the second conductive elements is adapted to allow electrical current to flow in series through respective pairs of N-type and P-type electrodes; and wherein the electrode pattern in the electrical insulator layer corresponds to a pattern of P-type electrodes.