Qinetiq Limited

The Secretary of State for Defence

Christopher Pickering

David John Robbins

Roger Timothy Carline

John L Glasper

John Russell

Allister W E Dann

Alan D Marrs

Layer processing to grow a layer structure upon a substrate surface comprises supplying a vapor mixture stream to the substrate ( ) to deposit constituents, monitoring growth with an ellipsometer ( ) and using its output in real-time growth control of successive pseudo-layers. A Bayesian algorithm is used to predict a probability density function for pseudo-layer growth parameters from initial surface composition, growth conditions and associated growth probabilities therewith, the function comprising discrete samples. Weights are assigned to the samples representing occurrence likelihoods based on most recent sensor output. A subset of the samples is chosen with selection likelihood weighted in favor of samples with greater weights. The subset provides a subsequent predicted probability density function and associated pseudo-layer growth parameters for growth control, and becomes a predicted probability density function for a further iteration of pseudo-layer growth.

Layer processing

A method of monitoring material parameters of a sample ( ) (for example electrical properties of a semiconductor) during processing (for example during manufacture) which uses ellipsometric techniques to study the changes induced in the ellipsometric spectra of the material, by modulation of the internal electric field of the material, and determining from these changes the material parameters of interest The means of modulation can be a source of electromagnetic radiation, for example a laser ( ). The ellipsometer used may include an array of photodetectors. The process allows the real time monitoring of the process under examination.

In-situ monitoring of electrical properties by ellipsometry

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Malvern, United Kingdom

Christopher Pickering