METHOD OF MAKING TRANSISTOR MICROWAVE LDMOS STRUCTURE Russian patent published in 2014 - IPC H01L21/336 

FIELD: physics.

SUBSTANCE: invention relates to semiconductor electronic engineering. The method of making a transistor microwave LDMOS structure deposited on a gate insulator involves coating polysilicon with a refractory metal; forming a polycide of the refractory metal; depositing a protective photoresist layer on the front side of the substrate; opening windows in the protective photoresist layer, the refractory metal polycide, polysilicon and the gate insulator over source p⁺-jumpers and adjacent portions of a high-ohmic p^--layer of the substrate, thereby initially forming only source lateral faces of polycide gate electrodes of the transistor cells; embedding boron ions into the substrate through the opened windows; removing the photoresist from the front surface of the substrate and, via subsequent diffusion distillation of the impurities embedded into the substrate, forming p-pockets of elementary cells; removing the refractory metal polycide and the polysilicon from the front surface of the substrate in the space between the p-pockets of the transistor cells and forming drain lateral faces of polycide gate cogs and polycide gate electrodes of the elementary cells overall; in the high-ohmic epitaxial p^--layer of the substrate at the source and in the space between the drain lateral faces of polycide gate electrodes, forming highly doped source n⁺-regions and highly doped and multi-stage weakly doped n-regions of the drain of the elementary cells; forming metal shielding electrodes of the transistor cells in the interlayer dielectric; pin-point shutting the polycide gate cogs of the cells with common metal gate buses formed on the top surface of the multilevel interlayer dielectric over source p⁺-jumpers of elementary cells.

EFFECT: basic process of making powerful silicon microwave LDMOS structures and transistors using cheaper equipment capable of operating in the frequency range of 3,0-3,6 GHz at high drain supply voltages.

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