Semiconductor device and method of making the same

Abstract

The invention discloses a semiconductor device and a manufacturing method thereof. The manufacturing method comprises a) providing a semiconductor substrate, on which a grid structure is formed, wherein shallow doped area are formed on two sides of the grid structure in the semiconductor substrate; b) forming a sidewall material layer on the semiconductor substrate and the grid structure, wherein the sidewall material layer comprises an oxide layer and a nitride layer alternatively formed; c) dry etching the sidewall material layer until exposing a lowest layer in the sidewall material layer; d) wet etching an exposed oxide layer or an exposed nitride layer so as to form sidewalls on two sides of the grid structure, wherein the residual oxide layer and the residual nitride layer posses different widths; and e) performing source-drain doping on the semiconductor substrate so that the semiconductor substrate corresponding with the sidewalls has doping gradients therein. The manufacturing method can effectively reduce hot carrier effect and enhance MOS device reliability.

Description

technical field [0001] The present invention relates to the technical field of semiconductors, in particular to a semiconductor device and a manufacturing method thereof. Background technique [0002] With the continuous development of semiconductor technology, the size of semiconductor devices continues to decrease, the channel length becomes very short, and the electric field strength between the source and drain is strong, which easily forms a large number of destructive hot carriers. Hot carriers will produce hot carrier effects, which will affect the reliability of semiconductor devices. [0003] At present, the hot carrier effect is usually reduced by reducing the maximum lateral electric field strength along the channel direction between the source and the drain. For example, in the fabrication process of sub-micron MOSFET devices, a lightly doped drain region (LDD) with a shallower doping concentration is formed between the source and drain to slow down the doping g...

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