Method of optimizing the EMI shielding and infrared transparency of GaAs IR windows

A method of designing and manufacturing an EMI shielded infrared (IR) window suitable for a specified application having specified size, transparency, and EMI shielding requirements, the method comprising:

• preparing a slab of GaAs or GaP according to the size requirement of the specified application, the slab having sufficient thickness to meet a structural competence requirement of the specified application;
• selecting a plurality of candidate parameter combinations comprising combinations of candidate dopant concentrations and candidate layer thicknesses for a doped conductive layer to be applied to the slab, the doped layer being a doped layer of GaAs if the slab is a GaAs slab, the doped layer being a doped layer of GaP if the slab is a GaP slab;
• applying a model to the candidate parameter combinations, thereby for each of the candidate parameter combinations estimating an IR absorption and a sheet conductivity of the doped conductive layer, wherein applying the model comprises:
• applying an empirical low field mobility model according to Sotoodeh, thereby estimating a carrier mobility of the doped conductive layer;
• calculating an estimated sheet resistance of the doped conductive layer according to the candidate parameters and the estimated carrier mobility;
• and
• applying a quantum mechanical defect scattering model of free carrier absorption based upon a relationship taught by Nag, thereby estimating the IR absorption of the doped conductive layer according to the candidate layer thickness and the estimated sheet resistance of the doped conductive layer;
• repeating the steps of selecting candidate parameters and applying the model thereto until an optimal combination of layer thickness and dopant concentration are determined;
• and
• if the model predicts that applying the doped semiconductor layer having the determined optimal combination of layer thickness and dopant concentration will meet the transparency and EMI shielding requirements of the specified application, applying the doped conductive layer to the slab according to the determined optimal combination of layer thickness and dopant concentration.