Groove type power MOS device and manufacturing method thereof

Abstract

The invention relates to a groove type power MOS device and a manufacturing method thereof. The device comprises an active region and a terminal protection region, wherein a first conduction type injection layer and a second conduction type layer pass through the whole terminal protection region, the terminal protection region is in a groove structure, and a first groove is formed in the terminalprotection region; an insulating oxide layer grows on the inner wall of the first groove, a first side wall protector and a second side wall protector are respectively arranged at two sides of the first groove, and the first side wall protector and the second side wall protector are isolated by utilizing an insulating dielectric layer; the first side wall protector is close to the active region, and the second side wall protector is far away from the active region; the first side wall protector is in zero potential; and a second metal layer is arranged above the terminal protection region corresponding to the second side wall protector, and the second side wall protector and the first conduction type layer substrate are connected by the second metal layer to have equal potential. The invention reduces the manufacturing cost of the MOS device and improves the pressure resistance of the MOS device.

Description

technical field [0001] The invention relates to a power semiconductor device, in particular to a trench type power MOS device and a manufacturing method thereof. Background technique [0002] Improving device performance and reducing device cost are two important driving forces for the continuous development of power semiconductor devices. An important part of power semiconductor devices: Trench-type power MOS (metal-oxide-semiconductor) devices have been continuously updated and developed, and a complete device manufacturing process can be realized through four photolithography processes, and has been Widely used in mass production of products. [0003] At present, Chinese patents ZL 200710302461.4 and ZL 200810019085.2 disclose "A Deep Trench High-Power MOS Device and Its Manufacturing Method", which relates to a trench-type power MOS device manufactured by quadruple photolithography; the trench The structure of the slot power MOS device is as attached in Chinese patent ...

AI Technical Summary

Problems solved by technology

[0005] In addition, the terminal protection area in the structures of Chinese patents ZL200710302461.4 and ZL200810019085.2 includes at least one voltage divider ring of trench structure, and the well layer of the second conductivity type exists in the entire terminal protection area, as shown in Figure 16.a ; but from the actual simulation results, when the device reverses the withstand voltage, the first trench structure voltage divider ring close to the active region bears most of the voltage drop, and because the depletion layer will be along the first The sidewall of a trench structure voltage divider bends up to the silicon surface, specifically, along the sidewall of the trench near the active region; The width of the depleted layer is much narrower, resulting in too dense potential lines in the depletion layer parallel to the sidewall of the trench, and it is easy to form an excessively strong electric field on the surface of the thin insulating gate oxide layer on the sidewall of the trench, reducing the Device withstand voltage reliability

Images