Method for forming monocrystalline silicon layer

Abstract

The invention provides a method for forming a monocrystalline silicon layer, which is used for a phase-change random-access memory. The method comprises the following steps of: providing a front-end device structure which comprises a cell array area and a peripheral circuit area; forming an oxide layer on the surface of the cell array area and the peripheral circuit area; forming a polycrystalline silicon seed-crystal layer on the oxide layer; etching the polycrystalline silicon seed-crystal layer and the oxide layer so as to remove parts of the polycrystalline silicon seed-crystal layer and the oxide layer in the cell array area, and retaining parts of the polycrystalline silicon seed-crystal layer and the oxide layer in the peripheral circuit area; and forming the monocrystalline silicon layer on the surface of the cell array area and the parts of the polycrystalline silicon seed-crystal layer and the oxide layer in the peripheral circuit area. In the method, the monocrystalline silicon layer with better uniformity can be provided in the peripheral circuit area, so that the integral uniformity of the monocrystalline silicon layer in the cell array area and the peripheral circuit area is improved, further the integral electric performance of the finally-formed PCRAM (phase-change random-access memory) can be improved, and the simplicity of the process flow can be realized.

Description

technical field [0001] The present invention relates to a method for manufacturing a semiconductor device, and in particular, to a method of forming a single crystal silicon layer for a phase change random access memory (PCRAM). Background technique [0002] As early as 1968, Ovshinsky first described the memory based on phase transition theory in his first published paper on phase transition of amorphous: material changes from amorphous state to crystal and In the process of changing back to the amorphous state, the amorphous and crystalline states exhibit different optical and resistive properties, so the amorphous and crystalline states can be used to represent "0" and "1" respectively to store data. Theoretically, the advantages of this kind of memory based on phase change theory are that the product is small in size, low in cost, can be written directly (that is, the original data does not need to be erased when writing data) and simple to manufacture (only need to be s...

AI Technical Summary

Problems solved by technology

[0012] like Figure 3A As shown in , in the cell array area, the thickness deviation of the grown single crystal silicon layer is about And in the peripheral circuit area, such as Figure 3B As shown in , the thickness deviation of the grown single crystal silicon layer exceeds Obviously, this makes it difficult to obtain good process uniformity during the manufacturing process, and the uniformity of the monocrystalline silicon layer in the peripheral circuit area is especially poor, resulting in poor electrical performance of the final formed PCRAM

Images