Abstract: The present invention discloses a self-aligned register structure for base polysilicon and a preparation method thereof. The self-aligned register structure comprises a silicon substrate having a partially oxidized region of SiO2 medium, a SiO2 medium protective layer is arranged at a center above the silicon substrate, base polysilicon layers are located at left and right sides of the SiO2 medium protective layer, the adjacent base polysilicon layers are symmetrical to the SiO2 medium protective layer at equal spacing, and the spacing is equal to a thickness of the base polysilicon layer.

Abstract: The present invention discloses a self-aligned register structure for base polysilicon and a preparation method thereof. The self-aligned register structure comprises a silicon substrate having a partially oxidized region of SiO2 medium, a SiO2 medium protective layer is arranged at a center above the silicon substrate, base polysilicon layers are located at left and right sides of the SiO2 medium protective layer, the adjacent base polysilicon layers are symmetrical to the SiO2 medium protective layer at equal spacing, and the spacing is equal to a thickness of the base polysilicon layer.

Abstract: A MOS transistor (60, 62) is provided. The structure of the transistor (60, 62) includes: a semiconductor substrate (10), a channel area (20, 24), source/drain regions (22, 26), a gate (30, 32), a gate insulating layer (11), a shallow trench isolation region (12), a passive layer (50, 52), and holes (40, 42) formed with a certain distance to the gate insulating layer (11). Wherein both the shapes of the holes (40, 42) and the Young's modulus' difference between the material in the holes (40, 42) and that around the holes (40, 42) contribute to the stress concentration effect, thus the stress in the channel area (20, 24) is enhanced. The structure of the transistor (60, 62) can greatly reduce the stress attenuation during the transmission from stress resource to the sensitive region, and concentrate the stress in the sensitive region. The structure can be involved in large size device, especially.