Optics: measuring and testing – By polarized light examination – Of surface reflection
Patent
1999-01-13
2000-10-03
Font, Frank G.
Optics: measuring and testing
By polarized light examination
Of surface reflection
356381, 250225, G01J 400, G02F 101
Patent
active
061280844
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a method for optically evaluating the characteristic of an amorphous region with crystallinity disordered by dopant ions implanted at a high level, a method for measuring a temperature and a method for fabricating a semiconductor device utilizing such evaluation, and a storage medium used for automatically making the evaluation.
BACKGROUND ART
In a fabrication process of a semiconductor device such as a transistor, when source/drain regions for a MOSFET, an emitter diffusion layer for a bipolar transistor and so on are formed, for example, ion implantation for accelerating and implanting ions such as P, As and B into a semiconductor substrate, a polysilicon layer or an amorphous silicon film has heretofore been utilized as a means for accurately controlling doping level of the dopant, depth of a region to be doped and the like. Recently, in order to meet a demand for miniaturization of semiconductor devices, the dopant concentration and thickness of a region formed by the ion implantation need to be controlled even more precisely.
For example, it is known that, when silicon atoms are scattered out of the normal sites thereof by dopant ions implanted into a single crystalline layer, an amorphous region is formed by these recoil silicon atoms. As a means for measuring the thickness and the like of such an amorphous region formed by these recoil silicon ions, Rutherford backscattering spectrometry (RBS) and the photograph of a cross section taken with a transmission electron microscope (TEM) are conventionally adopted.
Ion implant energy and dose of dopant ions implanted into a silicon substrate are conventionally estimated by 4-terminal sheet resistance measurement or thermal wave method. Similarly, the uniformity of the dopant concentration of an ion implanted layer formed on a silicon substrate in a silicon wafer by the ion implantation is also estimated by 4-terminal sheet resistance measurement or thermal wave method.
On the other hand, ellipsometry, obtaining information such as complex refractive index and thickness by making linearly-polarized light incident on the surface of a substrate at a tilt angle and measuring an elliptical shape of elliptically-polarized light reflected from the substrate surface, is known as a simple optical evaluation method.
Problems to be Solved
However, when these evaluation methods are applied to the characterization during the actual fabrication process of a semiconductor device, the following problems arise. And it has been difficult to evaluate whether or not the implantation conditions are appropriate for a region implanted with ions at a high level, in particular.
First, the RBS and the TEM are destructive test methods, and hence are not suitable for evaluation in the production line of semiconductor devices.
Furthermore, when a region implanted with a dopant at a high level is evaluated by the sheet resistance measurement, the measurement is considerably affected by a heat treatment because accelerated diffusion is locally caused due to the damage resulting from the ion implantation. Accordingly, it is impossible to evaluate the ion implantation conditions by themselves.
In accordance with the thermal wave method, the ion implant energy and the concentration of implanted ions are estimated by measuring a damage in an implanted layer. In a region implanted with an impurity at a high level, however, it is difficult to identify the difference in implant doses, because the degree of the damage reaches a saturation region of detection sensitivity. In addition, since a value detected is not an absolute magnitude but a relative value, high detection sensitivity cannot be expected as to such a region implanted at a high level.
The present invention was made in view of these problems. The object of the present invention is to provide an evaluation method of a semiconductor layer, by which the thickness of an amorphous region, having crystallinity disordered by dopant ions implanted into the semiconductor layer at a hig
REFERENCES:
patent: 5229304 (1993-07-01), Chang et al.
patent: 5978074 (1999-11-01), Opsal et al.
Nanbu Yuko
Shibata Satoshi
Font Frank G.
Matsushita Electronics Corporation
Smith Zandra V.
LandOfFree
Evaluation method of semiconductor layer, method for fabricating does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Evaluation method of semiconductor layer, method for fabricating, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Evaluation method of semiconductor layer, method for fabricating will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-201061