Regina Hayn

A Growth Kinetics Model for the Radical Oxidation of Silicon

The silicon oxide growth kinetics were investigated for single wafer rapid thermal (RTP) and large batch vertical furnace radical oxidation processes under varying conditions. An oxidation model is proposed in which the oxidation rate of hydrogen–assisted radical oxidation is a combination of constant–rate low pressure wet oxidation and an oxygen radical driven process decaying with increasing oxide thickness. The model parameters for selected RTP and batch furnace oxidation processes are extracted and discussed. The implications of this model are compared to observed properties of the radical oxidation process like lattice orientation, stress independence, bird’s beak formation and thickness uniformity.

Characterization of nitrided gate oxides under manufacturing conditions

Silicon oxynitride gate dielectrics grown by plasma nitridation of RT radical oxide with subsequent post nitridation oxidation where characterized by different metrology methods like optical ellipsometry, X-ray photoelectron spectroscopy, corona characterization of semiconductors (Cocos), time-of-flight secondary ion mass spectroscopy and end-of-line transistor parameters. Several design of experiments where performed where the influence of process variation on the monitoring results where investigated. It could be shown, that the capacitance equivalent thickness in-line measured by Cocos provides a sensitive control parameter for most process variations.

Non-contact characterization of several silicon oxides oxynitrides grown by rapid thermal processing

The electrical properties of several potential gate dielectric materials as silicon oxides and oxynitrides with thicknesses of 15-35 Aring have been analyzed by the corona characterization of semiconductor (Cocos) method. The silicon oxides are grown by conventional furnace as well as by wet and radical RT oxidation processes while the silicon oxynitrides represented by reoxidized RT nitride and plasma nitrided RTO films. The influence of the different growth techniques as well as hydrogen and inert post anneals have been studied in order to investigate their influence especially on interface state density and flatband voltage. In case of silicon oxynitride films, time-of-flight secondary ion mass spectrometry was done to determine the content and distribution of oxygen and nitrogen. The preparation free non-contact method of the corona characterization was used to obtain electrical parameters as equivalent oxide thickness, interface state density, flatband voltage and oxide leakage. It could be shown that with this comprehensive set of parameters the in-line monitoring of advanced RT grown gate dielectrics can be performed