Transistors and methods of forming them

Abstract

The invention provides a transistor and a forming method thereof. The forming method comprises: a base including a substrate, a stress constraint layer and a channel layer are provided, wherein the stress constraint layer and the channel layer are arranged on the surface of the substrate successively; a gate structure is formed on the base; the channel layer at the two sides of the gate structure are removed and grooves are formed in the sidewall of the remaining channel layer; the stress constraint layer at the two sides of the gate structure is removed and the base at the two sides is removed with a certain thickness to form a first opening; and the first opening is filled to form a stress layer. Because the stress constraint layer is arranged in the base, the stress layer arranged at the two sides of the gate in the base has a part having a protrusion in the channel layer and a part in the stress constraint layer and the substrate. The protrusion of the stress layer in the channel layer enables stresses to be led into a channel in the channel layer; the stress layer in the stress constraint layer and the substrate enables the size of the stress layer to be increased, so that the stress of the channel region can be increased. Therefore, the migration rate of carriers in the channel can be improved, so that the transistor performance can be 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] Transistors are currently being widely used as the most basic semiconductor devices. As the density and integration of components in integrated circuits increases, the size of transistors becomes smaller and smaller. As the size of the transistor shrinks, the channel length and the gate length of the transistor are also shortened. The shortening of the channel length of the transistor makes the approximation of the slowly-varying channel no longer valid, causing the short-channel effect, and then generating leakage current, which affects the performance of semiconductor devices. By introducing stress to the channel region of the transistor, the mobility of carriers in the channel can be increased, thereby increasing the driving current of the transistor, thereby suppressing the leakage current of...

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Problems solved by technology

[0004] However, the carrier mobility in the channel region of the transistor in the prior art is still low, which cannot better improve the performance of the semiconductor device.

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