A silicon-based thin epitaxial single-resurf level-shift structure

Abstract

The invention relates to a silicon base thin epitaxial single RESURF level displacement structure, which belongs to the technical field of semiconductor power devices. Including floating ground-based high-end circuits, terminals, LDMOS, the first bend area, and the second bend area; for the first bend area, increase the curvature radius of the drain to meet the withstand voltage requirements; for the second bend area, increase The length of the drift zone in the second bend area is large, and the optimized drift zone length will weaken the electric field concentration of the curvature junction, avoid the concentration of electric field lines at the source end, and will obtain a longer voltage withstand layer to avoid early breakdown, thereby improving bend channel breakdown voltage. The level displacement structure of the present invention can prevent the electric field on the surface of the curvature terminal with the source in the center from being too concentrated, and reduce the influence of the curvature on the withstand voltage of the device; compared with the existing curvature terminal processing method, the present invention does not introduce a new version or The process flow is low in cost, and the process is compatible with the standard CMOS process flow, which realizes the integration of the level-shift structure of the high-voltage integrated circuit.

Description

technical field [0001] The invention belongs to the technical field of semiconductor power devices, and in particular relates to a silicon-based thin epitaxial single RESURF level displacement structure. Background technique [0002] A high-voltage integrated circuit is composed of a low-voltage area and a high-voltage area. When the high-voltage and low-voltage devices are integrated on the same chip in a power integrated circuit, in order to realize the function of transmitting the low-end control signal to the high-end, it is often unavoidable that there will be hundreds of volts High-voltage interconnect lines HVI with even thousands of volts cross over low-voltage devices, partial areas on the surface of isolation regions, or low-voltage portions of high-voltage devices. The high potential on the interconnect lines affects the electric field distribution on the Si surface at the high-voltage junction termination, reducing its withstand voltage. [0003] High-voltage po...

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Problems solved by technology

[0005] Aiming at the problems existing in the background technology, the present invention proposes a silicon-based thin epitaxy single RESURF level shift structure to solve the shortcomings of traditional thick epitaxy technology such as long thermal process time, large lateral diffusion of junction isolation, and blurred lithographic marks after thick epitaxy.

[0007] In order to solve the problem of early breakdown of the device caused by the thin epitaxial curvature effect, the present invention proposes a silicon-based thin epitaxial single RESURF level shift structure, such as Figure 4 As shown, it includes a high-end circuit 402 based on a floating ground, a terminal 403, an LDMOS 401, a first curved area 405, and a second curved area 404; for the first curved area 405, the curvature radius of the drain is increased to meet the withstand voltage requirement; For the second bend region 404, increase the length of the drift region in the second bend region. The optimized drift region length will weaken the electric field concentration of the curvature junction, avoid the concentration of electric field lines at the source end, and obtain a longer withstand voltage layer , to avoid premature breakdown, thereby increasing the breakdown voltage in the bend area

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