AVS 53rd International Symposium
    Applied Surface Science Thursday Sessions
       Session AS-ThP

Paper AS-ThP15
Doping Area Analysis using Atomic Force Microscopy in Si Devices

Thursday, November 16, 2006, 5:30 pm, Room 3rd Floor Lobby

Session: Aspects of Applied Surface Science Poster Session
Presenter: K.-W. Kim, Hynix Semiconductor Inc., Korea
Authors: K.-W. Kim, Hynix Semiconductor Inc., Korea
E.-J. An, Hynix Semiconductor Inc., Korea
K.-Y. Choi, Hynix Semiconductor Inc., Korea
S.-Y. Lee, Hynix Semiconductor Inc., Korea
Correspondent: Click to Email
In the fabrication of nano-scale silicon devices, accurate doping area characterization is one of the important fields to be solved. Characterization methods such as scanning capacitance microscopy (SCM) and scanning spreading resistance microscopy (SSRM) have provided two-dimensional profiling of the carrier distribution in semiconductors. In this study, the possibility and the effectiveness of applying the atomic force microscopy (AFM)-imaging combined with delineation method are discussed for two-dimensional dopant profiling. Shallow junctions were fabricated in p-type silicon wafers by the implantation of As ions (~10e15/cm@super2@) at an energy of 55keV. Also selective etching was successfully performed using the chemical etching solutions of HF:HNO@sub3@:CH@sub3@COOH mixture. We found that different etching rates of the doped regions resulted in a surface topography, height difference and surface roughness. The reason for the visibility of dopant distribution is the relatively strong changes of the etching rate and the stained surface roughness in dependence on the doping concentration. We focused on evaluating an adequate roughness, etch line profile and the junction depth position in the junction area. The resulting dopant profile shapes and junction depth resembled the ones as measured by secondary ion mass spectroscopy (1-D), transmission electron microscopy combined with delineation and SCM (2-D). The spatial resolution of the chemical delineation was extremely good (better than 10nm) due to the capabilities of the AFM-microscope. Especially, dopant depth profiles of arsenic showed the similar values of junction depth (~200nm) at the above methods for a medium dose range. Further investigations are required that the accuracy of the measurement is determined by the repeatability of the etching procedure and the dopant concentration is related to the delineated surface roughness quantitatively.