FinFET device and manufacturing method thereof

Abstract

The invention provides an FinFET device and a manufacturing method thereof. The manufacturing method comprises the steps of a. providing a substrate on which a fin is disposed; b. forming shallow trench isolation on the substrate and at two sides of the fin; c. forming a protective mask at the two sides of the fin; d. thinning the shallow trench isolation to expose the fin partially; e. forming an isolation oxide layer on the fin that is not covered by the shallow trench isolation and the protective mask; f. removing the protective mask, and thickening the shallow trench isolation so as to be level with the isolation oxide layer; and g. forming a source and drain region, a gate structure and an interlayer dielectric layer in sequence on the thickened shallow trench isolation. According to the invention, the method of forming the oxide isolation layer in a region below a device trench allows a bulk silicon device have similar performance to an SOI device, and the punch-through current can be effectively suppressed without affecting other parameters of the device.

Description

technical field [0001] The present invention relates to a method for manufacturing a semiconductor device, in particular to a method for manufacturing a FinFET. technical background [0002] As the size of the semiconductor device is scaled down, there arises a problem that the threshold voltage decreases with the decrease of the channel length, that is, a short channel effect is generated in the semiconductor device. To meet the challenges from semiconductor design and manufacturing, led to the development of Fin Field Effect Transistor, or FinFET. [0003] Channel punch-through effect (Channelpunch-througheffect) is a phenomenon that the source junction and the depletion region of the drain junction of the field effect transistor are connected. When the channel is penetrated, the potential barrier between the source and the drain is significantly reduced, and a large number of carriers are injected from the source to the channel, and drift through the space charge region ...

AI Technical Summary

Problems solved by technology

The current general doping method is ion implantation to form the required heavily doped region. However, the depth of ion implantation is difficult to control precisely, and at the same time it will cause damage to the channel surface. In order to eliminate the damage, a thin layer is usually formed on the channel surface. Oxide layer, increasing process complexity

At the same time, the distribution of impurities is difficult to control, and it is difficult to accurately form an ultra-steep inverted well at the bottom of the channel. Instead, impurities and defects will be introduced into the channel, which will affect the subthreshold characteristics of the device.

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