Preparation method of nickel silicon alloy

Abstract

The invention discloses a preparation method of nickel silicon alloy. Before the nickel silicon alloy is prepared, low-temperature oxygen treatment, wet immersion pre-cleaning and silicon-cobalt-nickel pre-cleaning are sequentially carried out, so as to remove a native oxide; a first rapid heat treatment technology is carried out to form nickel silicon metal; the unreacted nickel silicon metal part is removed; a second rapid heat treatment technology is carried out to form the nickel silicon alloy, wherein the low-temperature oxygen treatment process is used for removing the defect of nonuniformity of a semiconductor device substrate due to the nonuniformity of the native oxide; the silicon-cobalt-nickel pre-cleaning process is used for removing the native oxide, so that the interfaces of the nickel silicon alloy and the silicon in the semiconductor device substrate are relatively stable and smooth; the thickness uniformity of the nickel silicon alloy is further improved; and pyramid defects caused by the native oxide are avoided, so as to improve the uniformity of contact resistance and prevent the semiconductor device from leaking electricity.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a method for preparing a nickel-silicon alloy used in semiconductor devices. Background technique [0002] At present, in the advanced CMOS process, the materials used as local interconnect (LI) and source-drain electrodes and gate electrode contacts mainly use nickel-silicon alloy thin films. Ohmic contact, reducing resistance. see figure 1 , which is a schematic flow diagram of an existing method for preparing a silicon nickel alloy, the existing method for preparing a silicon nickel alloy includes the following steps: [0003] Step L1: provide the semiconductor device substrate, and perform wet immersion pre-cleaning; used to remove organic matter and impurity particles; the semiconductor device substrate may include structures formed in the previous process; the material of the semiconductor device substrate usually contains silicon ; [0004] Step L2: depositing a...

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Problems solved by technology

[0008] However, in the above-mentioned preparation method, there is a defect: before step L1, since there is a thin original oxide layer on the original substrate used for the semiconductor device substrate, the growth of the original oxide layer is not uniform, resulting in The original substrate is consumed unevenly, thereby causing the unevenness of the formed semiconductor device substrate; and, in step L1, the pre-cleaning process adopted is a wet cleaning process, mainly for the purpose of removing organic matter and impurities, However, this wet cleaning process cannot effectively remove the native oxide on the semiconductor device substrate; in subsequent steps, the native oxide on the surface of the semiconductor device substrate is sandwiched between the semiconductor device substrate and the formed silicon nickel alloy Between, that is, there is a native oxide at the interface of silicon / silicon nickel, so that nickel reacts with the native oxide during diffusion to form SiNiO, NiO 2 、SiNi 2 Crystals with equal high resistance are called pyramid defects because their shape resembles the shape of an Egyptian pyramid, such as figure 2 As shown, the arrow points to the pyramid defect

[0009] Due to the existence of pyramidal defects, the interface between Si on the semiconductor device substrate and NiSi in the nickel-silicon alloy is uneven, has sharp corners, and is prone to leakage

And it also causes the nickel silicon metal layer to be uneven; because the contact resistance of the nickel silicon metal layer has a great relationship with its thickness, the uneven nickel silicon alloy layer seriously affects the contact resistance of the nickel silicon alloy, so the pyramid defect Seriously affects the uniformity of contact resistance of nickel-silicon alloy

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