Semiconductor structure and forming method thereof

Abstract

The invention discloses a semiconductor structure and a forming method thereof, the structure comprises a substrate, the substrate comprises a substrate and a fin part protruding out of the substrate, the substrate comprises a first device region and a second device region along the direction vertical to the extension direction of the fin part, the device working voltage of the second device region is greater than the device working voltage of the first device region, and the fin part is arranged in the first device region; the fin parts of the first device region and the second device region are equal in height; the isolation layer is located on the substrate exposed out of the fin part, the isolation layer covers part of the side wall of the fin part, and the top of the isolation layer in the second device region is higher than the top of the isolation layer in the first device region; the first gate oxide layer is located in the second device region and covers the fin part exposed out of the isolation layer in a shape-preserving manner; and the second gate oxide layer is located in the first device region and covers the fin part exposed out of the isolation layer in a shape-preserving manner, and the thickness of the second gate oxide layer is smaller than that of the first gate oxide layer. The top of the isolation layer in the second device region is higher than the top of the isolation layer in the first device region, thereby improving the filling performance of the gate structure in the second device region.

Description

technical field [0001] Embodiments of the present invention relate to the field of semiconductor manufacturing, and in particular, to a semiconductor structure and a method for forming the same. Background technique [0002] With the gradual development of semiconductor process technology, the development trend of semiconductor process nodes following Moore's Law is decreasing. In order to adapt to the reduction of the process node, the channel length of the MOSFET field effect transistor is correspondingly shortened. However, with the shortening of the channel length of the device, the distance between the source and the drain of the device is also shortened, so the control ability of the gate to the channel is deteriorated, and the difficulty of pinch off the channel by the gate voltage is also reduced. Increasingly large, the phenomenon of subthreshold leakage (subthreshold leakage), the so-called short-channel effect (SCE: short-channel effects), is more likely to occur...

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Problems solved by technology

However, as the channel length of the device shortens, the distance between the source and the drain of the device also shortens, so the control ability of the gate to the channel becomes worse, and the difficulty of pinching off the channel by the gate voltage also increases. It is getting bigger and bigger, making subthreshold leakage (subthreshold leakage), the so-called short-channel effect (SCE: short-channel effects) more likely to occur

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