Transverse diffusion field effect transistor and manufacturing method therefor

Abstract

The invention discloses a transverse diffusion field effect transistor. The transverse diffusion field effect transistor comprises a second-conductive-type-doped buried layer formed in a first-conductive-type-doped drifting region; the buried layer is provided with multiple buried layer sections with different concentrations and different depths; each adjacent two buried layer sections are arranged in a staggered manner longitudinally, so that a JFET effect between a channel region and the drifting region is lowered, and the current conduction region in the drifting region is enlarged when the device is conducted; the doping concentration of the buried layer section nearest to the channel region is greater than that of other buried layer sections; and due to the doping concentration of the buried layer section nearest to the channel region, the auxiliary drifting region on the side face of the channel region can be fully depleted at the initial stage of a drain terminal voltage. The invention also discloses a manufacturing method for the transverse diffusion field effect transistor. By adoption of the transverse diffusion field effect transistor, the low voltage breakdown can be prevented, the breakdown voltage can be increased, the conduction region of the leakage current can be enlarged, and the conduction resistance of the device can be lowered.

Description

technical field [0001] The invention relates to the field of semiconductor integrated circuit manufacturing, in particular to a lateral diffusion field effect transistor; the invention also relates to a manufacturing method of the lateral diffusion field effect transistor. Background technique [0002] Ultra-high voltage lateral diffusion field effect transistor (LDMOS) usually inserts a buried layer opposite to the conductivity type of the drift region in the drift region. The buried layer can help the drift region to be depleted, so that the concentration of the drift region can be appropriately increased, and the ultra-high voltage LDMOS can also be guaranteed. breakdown voltage. [0003] like figure 1 Shown is a schematic diagram of the structure of the existing lateral diffusion field effect transistor; taking N-type LDMOS as an example, the existing LDMOS includes: [0004] The drift region 102 is composed of a deep N well formed in a P-type semiconductor substrate s...

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Problems solved by technology

[0015] like Figure 2B shown, is figure 1 The depletion region simulation diagram of the existing device shown; it can be seen that the drift region in the region corresponding to the dotted circle 203 has not been fully depleted

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