Method of improving deposition

Details Method of improving deposition Method of improving deposition

2000-05-02

2001-11-20

Nelms, David (Department: 2818)

Semiconductor device manufacturing: process

Radiation or energy treatment modifying properties of...

Ionized irradiation

C438S695000, C438S706000, C438S723000, C438S734000, C438S743000, C438S745000, C438S748000, C438S753000, C438S756000

Reexamination Certificate

active

06319861

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process in the manufacturing of semiconductors. More particularly, the present invention relates to a treatment process capable of improving the quality of a deposited layer in a selective deposition.
2. Description of Related Art
In the manufacturing of semiconductors, selective deposition is often used to form different material layers, each having a desired thickness so that time-consuming and costly lithographic operations can be eliminated. For example, in the fabrication of the source/drain region of a MOS device having a shallow junction design, selective deposition deposits a silicon (or germanium) layer above the source/drain region to form a raised source/drain terminal. The raised source drain terminal is capable of preventing a junction leakage that results from the removal of a portion of the silicon material from the shallow junction layer above the source/drain region in a subsequent metal silicide reaction.
However, due to atmospheric oxidation, a native oxide layer having a non-uniform thickness but averaging at about 20 Å is generally formed over the surface of a silicon layer. Hence, when a material is deposited over the silicon layer by selective deposition, dislocation, stack faults, uneven distribution and insufficient selectivity of the deposited material layer often occur. In brief, native oxide is a major drawback for selective deposition of material layers.
The conventional method of removing the effect due to the presence of a native oxide layer includes implanting boron difluoride ions BF
2
+
into the silicon substrate before carrying out the selective deposition of silicon (germanium) over the source/drain region. However, since an ion implantation may change the electrical properties of the substrate, the treatment can be applied to prime either a NMOS or a PMOS transistor, but not both. Furthermore, ion implantation and the selective deposition of silicon (germanium) cannot be carried out in the same reaction chamber, thereby adding some complications to the processing method.
SUMMARY OF THE INVENTION
Accordingly, one object of the present invention is to provide a process treatment for removing a native oxide layer from the surface of a silicon substrate in order to improve the quality of the subsequently deposited layer in a selective deposition.
To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention provides a treatment process for removing native oxide from the surface of a silicon substrate. First, a plasma reaction of the substrate is carried out using a halogen compound as a gaseous reactant so that the native oxide layer is transformed into a silicon halide layer. The silicon halide layer is next removed at a low pressure. Finally, a layer of the desired material is deposited over the silicon substrate in a selective deposition. Since the kinetic energy of the plasma in the plasma reaction can be accurately controlled, damage to the silicon substrate under the native oxide layer is limited.
The desired material layer is deposited over the silicon substrate after the native oxide layer is removed. Hence, the material is formed on a structurally uniform silicon surface so that such defects as dislocation, stack faults, uneven distribution of the deposited layer and insufficient selectivity of the deposition are absent.
In addition, any other processes that demand a clean and smooth silicon surface may apply the method suggested in this invention to remove the native oxide layer. For example, the method can be applied to remove surface native oxide from a silicon substrate before carrying out thermal reactions to form an oxide layer, or, a silicide reaction to form a metal silicide layer.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.


REFERENCES:
patent: 6008128 (1998-06-01), Habuka et al.
patent: 6027970 (2000-02-01), Sharan et al.
patent: 6048782 (2000-04-01), Moslehi
patent: 6090721 (1999-06-01), Yates
patent: 6159859 (1998-06-01), Robertson, III et al.

Affiliated with

Also associated with

Rating

Method of improving deposition does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Method of improving deposition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of improving deposition will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2608783