Radiation-resistant fdsoi field effect transistor with sonos structure based on 22nm process and its preparation method

Abstract

The invention relates to a SONOS structure radiation-resistant FDSOI field effect transistor based on a 22nm process and a preparation method thereof. The method includes: making a SONOS structure, making a back gate, making a shallow trench isolation, making a back plate doping, making a high-K gate oxide and polysilicon gate, making the first layer of Si 3 N 4 Side walls, lightly doped source and drain, source and drain protrusions, source and drain regions, surface cleaning, and the device is completed. The present invention adds Si to the common BOX layer 3 N 4 layer, the BOX layer is divided into upper and lower layers, the introduced potential barrier increases the recombination of electrons and holes, and reduces the number of traps trapped in the BOX layer under the action of irradiation. 3 N 4 The trapped negative charges are generated in the layer, which offsets the effect of a part of the trapped positive charges in the BOX layer, so that the depth of the channel near the interface of the BOX layer is not easy to inversion, and the radiation resistance performance of the device is improved.

Description

technical field [0001] The invention belongs to the technical field of semiconductor devices, and relates to a SONOS structure anti-radiation FDSOI field effect transistor based on a 22nm process and a preparation method thereof. Background technique [0002] With the rapid development of the semiconductor industry, ordinary bulk silicon MOS (metal-oxide-semiconductor) devices can no longer meet the needs of the industry, and FDSOI (fully depleted silicon-on-insulator) devices are The leakage current has become an option to replace bulk silicon devices. FDSOI devices have significant advantages of high performance and low power consumption. The BOX layer (buried oxide layer) and the very thin top silicon layer can significantly reduce parasitic capacitance and junction leakage current. These excellent characteristics are important for semiconductor integrated circuits to continue to chase Moore's Law. significant. And because of its all-dielectric isolation structure, it h...

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Problems solved by technology

[0003] However, since there is no BOX structure as the device feature size shrinks, it is still sensitive to the total dose effect

Irradiation generates a large amount of trapped charges in the BOX layer, and then forms a leakage path at the lower interface of the channel, which leads to a decrease in the threshold voltage of the FDSOI device, an increase in the off-state leakage current, and degradation of subthreshold characteristics.

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