Metal oxide semiconductor field effect transistor and manufacturing method thereof

Abstract

The invention relates to a metal oxide semiconductor field effect transistor and a manufacturing method thereof. A first groove and a second groove are formed at one side of a N-type substrate at intervals, the N-type substrate and the inner walls of the grooves are covered by the gate oxide layer, the part, located between the first groove and the second groove, of the gate oxide layer is coveredby the polycrystalline silicon layer, and the polycrystalline silicon layer fills the first groove and the second groove. When the P-type ions are injected, the implantation dose of the P-type ions is increased, and when the p-type ions are subsequently driven in, the p-type ions are diffused to an area which is located between the first groove and the second groove and is close to one groove andan area below the groove. Due to the transverse blocking effect of the grooves, the transverse diffusion of a P-region is not too large, meanwhile, the doping concentration of a channel region is nottoo high, and the working turn-on voltage of the device is not affected. The dosage of the P-region is increased compared with a traditional method, so that the doping concentration of the whole P-region is increased, and the EAS parameters of the device are greatly improved.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a metal oxide semiconductor field effect transistor and a manufacturing method thereof. Background technique [0002] For a power MOSFET (Metal Oxide Semiconductor Field Effect Transistor) device, in order to increase the important parameter EAS (single-pulse avalanche breakdown energy) of the device, it is necessary to increase the doping concentration of the P-body region. However, increasing the doping concentration of the P-body region will cause the lateral diffusion of the P-body region to be too large, and the large lateral diffusion will inevitably cause the area of ​​the device to become larger. At the same time, because the doping concentration of the P-region increases, It will also cause the working turn-on voltage of the device to be too high. Therefore, in the conventional manufacturing process of MOSFET devices ( figure 1 In the above-mentione...

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Problems solved by technology

[0010]However, the P+ region obtained by this manufacturing method is too small, and the diffusion depth is not enough, so the improvement effect on the EAS of the device is not obvious enough

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