Trench type high-voltage isolation capacitor device based on Trench process and preparation method

Abstract

The invention relates to a trench type high-voltage isolation capacitor device based on a Trench process and a preparation method, at least four grooves are formed in a silicon substrate, high-temperature oxidation is performed on the silicon substrate on the side surfaces and the bottom surfaces of the grooves and the upper surface of the silicon substrate to form a silicon dioxide dielectric layer, polycrystalline silicon is filled in the grooves, grounding polycrystalline silicon is formed in the leftmost groove and the rightmost groove, high-voltage isolation capacitor polycrystalline silicon is formed in the middle groove, an insulation covering silicon dioxide layer and an insulation covering silicon nitride layer are arranged on the upper surface of the polycrystalline silicon, a contact hole is formed in the insulation covering layer, and a grounding polycrystalline silicon extraction electrode and a high-voltage isolation capacitor polycrystalline silicon extraction electrode are arranged in the contact hole. The capacitor device is high in voltage resistance and simple in structure, the preparation method solves the problem that the thickness of the silicon dioxide dielectric layer of the capacitor device is difficult to grow, and high isolation voltage of the capacitor device is achieved.

Description

technical field [0001] The invention belongs to the technical field of integrated circuits, and specifically provides a trench-type high-voltage isolation capacitor device based on Trench technology and a preparation method. Background technique [0002] Galvanic isolation refers to a way to prevent current from flowing directly from one area to another in a circuit, that is, no direct current flow path is established between the two areas. Although electricity cannot flow directly, energy or information can still be transmitted by other means, such as capacitance, inductance, or electromagnetic waves, or by optical, acoustic, or mechanical means. [0003] The birth and development of isolators have always been accompanied by the development of the power industry. The birth of the isolator is due to the filtering of industrial field noise and high and low frequency pulse signal interference and the isolation and protection of the control system to ensure the accuracy, stabi...

AI Technical Summary

Problems solved by technology

[0009] The thermal growth process of silicon dioxide exhibits an exponential decay characteristic. The initial growth rate of silicon dioxide is fast, but it is difficult to continue to grow after reaching a certain thickness. The conventional solution is to stack multiple layers of silicon dioxide and metal layers, which will It will lead to an increase in process cost. At the same time, the parasitic capacitance from the bottom metal plate to the silicon substrate (usually grounded) is much larger than the high-voltage isolation capacitor, which affects the signal transmission of the high-voltage isolation capacitor.

Images