Transistors and methods of forming them

Abstract

The invention relates to a transistor and a forming method thereof. The transistor comprises a semiconductor substrate, and a gate structure located on the semiconductor substrate, wherein the gate structure comprises a gate medium layer and a gate electrode located on the surface of the gate medium layer, the gate electrode has a middle region and marginal regions located at both sides of the middle region, and work function adjusting ions are doped in the middle region of the gate electrode, so that the work function of the middle region of the gate electrode is different from work functions of the marginal regions of the gate electrode. Under fixed gate voltage, the density of current carriers in a channel region is improved, and performance of the transistor is improved.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a transistor and a forming method thereof. Background technique [0002] Metal-oxide-semiconductor (MOS) transistors are the most basic devices in semiconductor manufacturing. They are widely used in various integrated circuits. According to the main carrier and the type of doping during manufacturing, they are divided into NMOS and PMOS transistors. [0003] The prior art provides a method for manufacturing a MOS transistor. Please refer to Figure 1 to Figure 3 The schematic cross-sectional structure diagram of the manufacturing method of the MOS transistor in the prior art is shown. [0004] Please refer to figure 1 , providing a semiconductor substrate 100, forming isolation structures 101 in the semiconductor substrate 100, the semiconductor substrate 100 between the isolation structures 101 is an active region, and forming a doped well (not shown) in the active...

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Problems solved by technology

[0009] However, in the conventionally formed transistor, the work function of the gate electrode 103 is constant across the channel region from the source region 112 to the drain region 113, which is not conducive to improving the performance of the transistor.

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