AVS 46th International Symposium
    Nanometer-scale Science and Technology Division Wednesday Sessions
       Session NS-WeP

Paper NS-WeP9
Non-destructive 1-D SCM Dopant Profiling Determination Method and Its Application to the 3-D Dopant Profiling

Wednesday, October 27, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: E.-S. Kang, Chung-Ang University, Korea
Authors: E.-S. Kang, Chung-Ang University, Korea
J.-W. Kang, Chung-Ang University, Korea
H.-J. Hwang, Chung-Ang University, Korea
Correspondent: Click to Email
As the scaling of feature size in the GSI device technology is continuing, the device characterization and life cycle is greatly affected due to an unexpected doping profile which is caused by 3-dimensional effects in mask corners and edges. Therefore, the experimentally determined 3-D impurity doping profile is needed to estimate these 3-D effects precisely. In this work, we present a new 1-D doping profiling determination method, which extends to the quantitative 3-D dopant profiling extraction. This is the non-destructive technique and method, which is different from conventional AFM/SCM measurement/dopant extraction and we can measure directly at real MOSFET device having 3-D structure. Through SCM modeling, we found the depletion layer in silicon was of a form of spherical capacitor with SCM tip biased. 2-D FDM (Finite Differential Method) code with SOR (Successive Over Relaxation) solver was developed to model the measurements by a SCM of a semiconductor wafer that contains an ion-implanted impurity region. And we analyzed this capacitor theoretically and determined the depleted total volume charge (Q), capacitance (C) and the rate of capacitance change with bias (dC/dV). It is very important to observe the depleted carriers movement in the silicon layer by applying a bias to tip. So we calculated the depleted volume charge considering some factors such as tip size, oxide thickness and applied bias (dc + ac) which has effect on the potential and depletion charge. Finally, we developed 1-D inversion algorithm to convert SCM measurement output (dC/dV) into real dopant concentration, comparing SCM signal output with the calculated dC/dV through SCM modeling. We assume 1-D Pearson distribution function having several parameters as the initial profile. This profile extraction procedures consist of finding the profile that minimizes the least squares fit criterion between the calculated dC/dV and the measured dC/dV.