Surface passivation method for Ge

Abstract

The invention belongs to the technical field of semiconductor manufacturing, and particularly discloses a surface passivation method for Ge. By adopting a thioacetamide (CH3CSNH2) solution to passivate a Ge sheet, the natural oxide on the surface of the Ge sheet can be removed, and an even and compact GeSx passivation layer can be generated to prevent the reoxidation of the surface of the Ge sheet and eliminate the Fermi level pinning. A layer of high-quality Al2O3 film is deposited on the passivated Ge sheet by adopting an atom layer deposition method to prevent the reoxidation of the surface of the Ge sheet, and therefore, a good Al2O3 / Ge interface can be obtained.

Description

technical field [0001] The invention belongs to the technical field of semiconductor manufacturing, and in particular relates to a substrate surface passivation process before the preparation of a semiconductor device, in particular to a germanium surface passivation method before the preparation of a germanium-based semiconductor device. Background technique [0002] The development of integrated circuit chips basically follows Moore's Law (Moore Law), that is, the integration level of semiconductor chips doubles every 18 months. In recent years, with the continuous development of microelectronics technology, integrated circuit chips have become smaller and faster, and the improvement of the driving current of metal-oxide-semiconductor (MOS) devices has become more important. The drive current of a MOS device is related to the ratio of gate width to gate length and carrier mobility. Due to the short channel effect, it is difficult to increase the ratio of the gate width to...

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Problems solved by technology

However, germanium does not have a very stable silicon dioxide film oxide layer like silicon, and the surface of Ge material is easily oxidized to form GeO with low dielectric constant, poor thermal stability and high defect density. x (x<2) layer, resulting in Fermi-level Pinning

Conventional chemical cleaning cannot completely remove the surface oxide of Ge, and in high dielectric constant (high k) dielectrics (such as HfO 2 ) in the deposition and subsequent thermal process, the germanium surface will still inevitably generate a low dielectric constant (low-k) interface layer and introduce a large number of defect levels, thereby affecting the electron mobility and reducing the performance of the MOS device, so We need to study germanium surface passivation technology

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