Vertical npn device in bcd process and its manufacturing method

Abstract

The invention discloses a vertical NPN device in a BCD process. An emitting region consists of a first N+ region and a second N- region, wherein the junction depth of the second N- region is greater than the junction depth of the first N+ region, in addition, the second N- region surrounds the peripheral side of the first N+ region, an embedded layer injection region is not formed right under the second N- region, and the junction depth of a base region positioned right under the second N- region does not expand towards the bottom through the low doping concentration of an embedded layer non-injection region. The invention also discloses a manufacturing method of the vertical NPN device in the BCD process. The second N-region of the device provided by the invention can carry out the transverse exhausting on the base region arranged at the bottom of the first N+ region, so that the BVEBO of the device can be improved. Through the arrangement of the embedded layer non-injection region of the device, the base region arranged right under the second N- region can expand towards the bottom, so that the influence of passing voltage reduction between CEs of the device due to the introduction of the second N- region can be reduced, and meanwhile, greater BVEBO and BVCEO can be obtained at the same time.

Description

technical field [0001] The invention relates to the field of semiconductor integrated circuit manufacturing, in particular to a vertical NPN device in the BCD process; the invention also relates to a method for manufacturing the vertical NPN device in the BCD process. Background technique [0002] The BCD process is a process that can make bipolar transistors (bipolar), CMOS and DMOS devices on the same chip, such as figure 1 Shown is a schematic structural diagram of a vertical NPN device in an existing BCD process; the vertical NPN device in an existing BCD process includes: [0003] A P-type silicon substrate 101 is formed with a highly doped N-type buried layer (NBL) 102 on the silicon substrate 101 . An N-type epitaxial layer is formed on the surface of the N-type buried layer 102, and the collector region 103 is composed of the N-type epitaxial layer. A field oxygen isolation layer 106 is formed on the surface of the N-type epitaxial layer, and an N-type sinking laye...

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Problems solved by technology

[0004] In the existing BCD process, by further performing N-type light doping, that is, N-implantation, on the emitter region 107, a graded emitter region (Graded Emitter) is formed to improve the PN junction between the emitter region and the base region of the NPN device, that is, EB The breakdown voltage of the junction, but due to the increase of N-implantation in the emitter region 107, the emitter region 107 will expand to the bottom, which will cause the width of the base region 104 to narrow, which will reduce the gap between the collector region and the emitter region of the device. The punch-through voltage is the CE-punch voltage

When the device is working, CE, that is, the punch-through (Punch) between the collector region and the emitter region may occur before the EB junction is broken down, which affects the device BV

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