Method for forming polycrystalline silicon-germanium layer

Abstract

The invention reveals a method for forming polycrystalline silicon germanium layer, using chemical gas-phase chemical precipitation, which uses Si2H6 (Disilane) and germanium containing gas as a precursor to make the reaction between 500 deg.C and about 600 deg.C, to form a polycrystalline silicon germanium layer on a gate dielectric layer as a gate. And the said polycrystalline silicon germanium layer is directly formed on the gate dielectric layer and provided with a uniform and flat surface.

Description

technical field [0001] The invention relates to a method for forming a polysilicon germanium layer, especially a method for directly forming a polysilicon germanium layer on an oxide layer without pre-forming a polysilicon seed layer (polysilicon seed layer). Background technique [0002] The rapid development of semiconductor manufacturing technology has allowed millions or even more circuit elements such as transistors to be laid out on a single integrated circuit chip. In order to achieve such a high device integration, not only the line width of the integrated circuit must be greatly reduced, but also the size of the common Metal-Oxide-Semiconductor Field Oxide Transistor (MOSFET) must be reduced. Metal-oxide-semiconductor field-effect transistors are also known as isolated gate field-effect transistors (Insulated Gate FieldOxide Transistor, IGFET), but most of the time they are called field-effect transistors. [0003] The miniaturization of field effect transistors is...

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Problems solved by technology

However, additionally forming a polysilicon seed layer on the oxide layer and then forming a polysilicon germanium layer will affect the electrical properties of the polysilicon germanium gate field effect transistor.

In addition, forming an additional polysilicon seed layer means an increase in cost, additional process variables and poor electrical properties. Therefore, there are still shortcomings to be overcome in the method of using a polysilicon seed layer to solve the surface roughness of the polysilicon germanium layer. This is the principle purpose of the invention

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