Novel Characterization Technique for Oxidation Processes

Abstract

A new application of the commercially-available Surface Charge Profiler (SCP) tool to evaluate metal ionic contaminants that can be brought in during device fabrication processes, including oxidation, is discussed. The SCP measures the surface photovoltage (SPV) signal, and associated depletion width (Wd) and the minority-carrier recombination lifetime (τ). The technique allows not only detect a risky level of the contaminants but also to distinguish between different impurities such as Fe, Cu, and Na. A behavior of these metals in the vicinity of Si-SiO2 interface is discussed. A novel characterization technique should be a beneficial alternative metrology to the conventional capacitance versus voltage (CV), triangular voltage sweep (TVS), and SPV methods.

Instability of Chemical Composition in PECVD BPSG film

“…To measure the change of the charge state on silicon surface beneath BPSG or LTO layer, the Surface Charge Profiler (SCP) tool was used. (5) The SCP measures a surface photo-voltage signal that is associated with the silicon-oxide interfacial charges. These positive charges invert the lightly doped silicon subsurface, inducing a depletion region in the silicon beneath the oxide.…”