Method for manufacturing field cut-off type insulated gate bipolar transistor

Abstract

The invention discloses a preparation method of a field cut-off type insulated gate bipolar transistor. The method comprises the following steps: taking a heavy doped N-type epitaxial layer formed through epitaxial growth on a substrate as a field cut-off layer, injecting N-type impurities into the field cut-off layer, taking a light doped N-type epitaxial layer formed through epitaxial growth as a voltage-withstanding layer, performing a conventional frontage process, preforming a back thinning process, injecting P-type impurities into the back and annealing to form a P-type collector region, and then performing a conventional back metallizing process. Through the adoption of the method disclosed by the invention, the production period is short, expensive high-energy ion injection equipment and laser annealing equipment are unnecessary, the cut-off layer thickness and the impurity concentration can be controlled according to device demand; the difficulty of the thinning process is reduced, the device performance is improved, and the process difficulty is reduced. The substrate selection is more free, and substrates in low costs can be selected.

Description

technical field [0001] The invention relates to the technical field of semiconductor devices, in particular to a preparation method of a field stop type insulated gate bipolar transistor. Background technique [0002] Insulated Gate Bipolar Transistor (Insulated Gate Bipolar Transistor, IGBT) is a new type of composite device that combines the advantages of power field effect transistors and power transistors. The transistor's low saturation voltage characteristics and the ability to easily realize a large current not only have the advantages of high input impedance, fast working speed, good thermal stability and simple driving circuit, but also have low on-state voltage, high withstand voltage and large current. The advantages, which make IGBT become a particularly attractive power electronics drive device in the field of power electronics in recent years, and have been more and more widely used. [0003] The development of IGBT has mainly experienced three types: punch-th...

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Problems solved by technology

Due to the protection of the front structure, the annealing temperature should not be too high. At this time, the impurity activation rate is very low, which affects the device performance.

Moreover, the ion implantation method on the back side cannot push the impurities into the deep layer, and can only obtain a thinner FS layer on the back side, which will affect the performance of the device.

There is also a method of forming a field stop layer by long-term diffusion and well pushing, and then epitaxially growing a voltage-resistant layer, but this method has a long production cycle, unsatisfactory concentration distribution, large concentration gradient, and difficulty in controlling the thinning thickness

Moreover, the above-mentioned backside ion implantation and laser annealing processes also require relatively expensive high-energy ion implantation equipment and laser annealing equipment, and the development cost is relatively large.

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