Fast reverse recovery method for SJ-MOS and device structure thereof
A fast reverse and epitaxy technology, used in semiconductor devices, semiconductor/solid-state device manufacturing, electrical components, etc., can solve the problems of increased IDSS, complex heavy metal doping process, high electron irradiation cost, and reduce reverse recovery time. The effect of small and minority carrier storage charge reduction and speeding up the reverse recovery process
Inactive Publication Date: 2017-05-31
XIAN LONTEN RENEWABLE ENERGY TECH
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Problems solved by technology
Generally, heavy metal doping or electron irradiation is used to reduce the minority carrier lifetime and trr, but both of these methods will lead to an increase in IDSS, and the heavy metal doping process is complicated, and the cost of electron irradiation is high
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[0026] The present invention will be described in detail below in combination with specific embodiments.
[0027] The method for fast reverse recovery SJ-MOS involved in the present invention specifically includes the following steps:
[0028] 1. Grow a certain thickness of epitaxial N- on the N+ substrate. ( figure 1 )
[0029] 2. After passing through the Trench photolithography plate, etch a deep trench ( figure 2 ).
[0030] 3. Grow a layer of shallowly doped N- - on the surface of the trench, with a thickness of about 1um. The doping concentration of this layer of epitaxy is low. The N-type epitaxy in step 1 ( image 3 ).
[0031] 4. Subsequently, grow a certain concentration of P+ epitaxy on the N-- epitaxy surface to fill the trench, and perform a CMP process to remove the N- - and P-type epitaxy outside the trench to form an N-column P-column phase Alternating superjunction structures ( Figure 4 ).
[0032] 5. Implant the body region through the Body photolit...
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The invention relates to a fast reverse recovery method for an SJ-MOS and a device structure thereof. The fast reverse recovery method comprises the following steps: generating an epitaxy N- on an N+ substrate; etching deep trenches by virtue of a Trench photo-etching plate; generating a layer of shallow-doped N- - on the surface of the trenches; generating a P+ epitaxy on the surface of an N- - epitaxy to ensure that the P+ epitaxy is completely filled in the trenches, carrying out a CMP process, and removing the N- - and P type epitaxies outside the trenches to form an N-column and P-column alternated super-junction structure; passing through a Body photo-etching plate injection body area and annealing to form a body area, oxidizing and back-etching in a deposition field, implementing gate-oxide and polysilicon deposition back-etching to form the gate, and then injecting As or P and implementing diffusion to form the Nsource; depositing an ILD and back-etching, implementing hole pouring, and finally depositing metals and back-etching to form the final structure of the device. According to the fast reverse recovery method disclosed by the invention, by adjusting the doping concentration distribution of the epitaxies, the purposes of reducing the stored charge of minority carriers and accelerating the reverse recovery process can be achieved, and thus the reverse recovery time can be significantly shortened.
Description
technical field [0001] The invention belongs to the technical field of semiconductor power devices, and in particular relates to a fast reverse recovery SJ-MOS method and a device structure thereof. Background technique [0002] It takes a certain amount of time for the parasitic body diode of SJ-MOS to conduct from forward conduction to reverse cutoff, because during forward conduction, a large number of minority carrier charges are stored in the pn junction region due to multi-substance diffusion. If it is set, the stored charge generated during forward conduction will form a reverse current, and it will take a certain amount of time to completely extract or recombine these reverse recovery charges. This process is called the reverse recovery process. In this process The time used in is called the reverse recovery time trr. A low reverse recovery time can speed up the turn-off time of the MOS tube, making the device suitable for higher operating frequencies. Generally, h...
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IPC IPC(8): H01L21/329H01L29/06H01L29/861
CPCH01L29/66128H01L29/0684H01L29/8611
Inventor 张园园周宏伟任文珍徐西昌
Owner XIAN LONTEN RENEWABLE ENERGY TECH