A high early voltage bipolar device and its manufacturing method

Abstract

The invention discloses a high Early voltage bipolar device and a manufacturing method thereof. The bipolar device includes three metal wirings and a substrate; an N buried layer, a first epitaxial layer, a second epitaxial layer and SiO 2 layer; 3 metal wires pass through the SiO 2 After the lead-out hole set on the layer, respectively connect the lead-out region of the collector region, the emitter region and the P-type base region; the lead-out region of the collector region and the P-type base region are located inside the second epitaxial layer, and the emitter region is located in the P-type base region Inside; P-type isolation regions are set on both sides of the bipolar device. The main improvement of the method is that it includes performing the first epitaxial process on the substrate to form the first epitaxial layer; performing the second epitaxial process on the first epitaxial layer to form the second epitaxial layer; through the design of the double epitaxial layer, it can Effectively increase the Early voltage, reduce the Early effect, and improve the precision of the integrated circuit; at the same time, the threshold voltage of the parasitic PMOS tube is increased, the metal wiring of the circuit is more convenient, and the working voltage range is expanded.

Description

technical field [0001] The invention belongs to the field of performance improvement of semiconductor devices, and relates to a high Early voltage bipolar device and a manufacturing method thereof. Background technique [0002] NPN transistor is a transistor structure often used in bipolar integrated circuits. In the production of traditional bipolar integrated circuits, an N-type epitaxial layer with desired resistivity and thickness is deposited on a P-type substrate, and is formed by ion implantation or diffusion process. The P-type impurity-doped base region, on the base region and the epitaxial layer, ion implantation or diffusion process is used to form the N-type impurity-doped emitter region and the lead-out region of the collector region, that is, the N-type epitaxial layer is selectively The P-type impurity doping forms the base region, and then selectively N-type impurity doping is performed on the P-type base region to form the emitter region, and at the same tim...

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Problems solved by technology

[0003] Traditional NPN transistors have low Early voltage and significant Early effect, which affect the accuracy of the circuit in integrated circuits with high demand. For example, when used as a reference source, the output fluctuation of the reference source increases due to the influence of the Early effect.

For NPN transistor circuits with high operating voltage, due to the low impurity concentration on the surface of the epitaxial layer, the parasitic PMOS threshold voltage is low, which affects the metal wiring of the circuit and the lower limit of the operating voltage

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