Recessed-type field effect transistor with reduced body effect

Abstract

For fabricating a field effect transistor, an extra-doped channel region is formed below a surface of a semiconductor substrate. An opening is formed in the semiconductor substrate into the extra-doped channel region. A gate insulator is formed at walls of the opening such that the extra-doped channel region abuts the gate insulator at a bottom portion of the opening. The opening is filled with a gate electrode. Such an extra-doped channel region prevents undesired body effect in the field effect transistor.

Description

BACKGROUND OF THE INVENTION [0001] This patent application claims priority to Korean Patent Application No. 2004-0009122, filed on Feb. 11, 2004 in the Korean Intellectual Property Office, the disclosure of which is hereby incorporated by reference in its entirety. 1. FIELD OF THE INVENTION [0002] The present invention relates generally to integrated circuit fabrication, and more particularly to fabrication of a recessed-type field effect transistor with an extra-doped channel region to reduce body effect. 2. DESCRIPTION OF THE RELATED ART [0003] Field effect transistors are a common component of many integrated circuits. A field effect transistor includes a source and a drain for defining a channel region, a gate insulator, and a gate electrode. The structure and operation of a field effect transistor is by now well known to one of ordinary skill in the art of electronics. [0004] As device dimensions are constantly scaled down, the channel length of the field effect transistor is c...

AI Technical Summary

Benefits of technology

[0012] In an example application, the field effect transistor is formed as part of a DRAM (dynamic random access memory) cell. In that case, the respective line pad disposed on the source is coupled to a storage capacitor of the DRAM cell, and the gate electrode forms a word line for the DRAM cell. However, the field effect transistor of the present invention may be applied for other types of integrated circuits.

[0013] In this manner, because the extra-doped channel region abuts the gate insulator at walls of the opening of the recessed type field effect transistor, body effect is prevented. Thus, the field effect transistor has a more stable threshold voltage for more stable operation.

Problems solved by technology

However, undesired short-channel effects result in the field effect transistor from such reduced channel length.

However, the anti-punch through layer in Wu is formed well below the opening such that the field effect transistor of Wu is still susceptible to undesired body effect.

In Wu, the anti-punch through layer does not abut the walls of the opening such that the anti-punch through layer does not prevent the undesired body effect.

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