Semiconductor device and method for manufacturing same

Abstract

The invention discloses a method for manufacturing a semiconductor device. The method includes the following steps of: providing a semiconductor substrate; forming a first semiconductor layer on the substrate, and forming a second semiconductor layer on the substrate and the first semiconductor layer, wherein first isolations are formed on the substrate, and the second semiconductor layer on the first semiconductor layer is an active area for forming a device structure; forming through etching holes in the second semiconductor layer on the first semiconductor layer; etching and removing the first semiconductor layer through the etching holes to form a cavity; forming a dielectric layer on the inner surfaces of the cavity and the etching holes, and adding conductor layers into the cavity and the etching holes to respectively form a back gate and connection holes; and forming second isolations of the device structure on the substrate at two side of the gate and between the first isolations and the back gate. According to the method, an SOI device can be obtained through the substrate; and through the dielectric layer formed on the cavity and the etching holes and the back gate formed by adding the conductor layers, the threshold voltage of the device can be adjusted, and the process is simple and is easy to operate.

Description

technical field [0001] The invention belongs to the field of semiconductor manufacturing, and in particular relates to a semiconductor device and a manufacturing method thereof. Background technique [0002] With the continuous reduction of the feature size of the device, after entering the nanometer scale, especially the size below 22nm, the problems close to the limit of semiconductor physical devices come one after another, such as capacitance loss, leakage current increase, noise promotion, latch-up effect and short channel In order to overcome these problems, SOI (Silicon-On-Insulator, Silicon-On-Insulator) technology came into being. [0003] The SOI substrate is divided into thick layer and thin layer SOI. The thickness of the top layer silicon of the thin layer SOI device is smaller than the width of the maximum depletion layer under the gate. When the thickness of the top layer silicon becomes thinner, the device is partially depleted (PartiallyDepletion) to fully d...

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Problems solved by technology

[0004] However, the current cost of SOI substrates is relatively high, and the specifications of the provided SOI substrates are relatively simple, so it is impossible to adjust the thickness of each layer according to the needs of the device.

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