Silicon nitride films having reduced interfacial strain

A method comprising:

• providing a silicon wafer;
• depositing a first portion of a silicon nitride layer on the silicon wafer;
• selectively removing first regions of the first portion of the silicon nitride layer along one or more dicing lanes to define one or more first gaps between areas of the first portion of the silicon nitride layer;
• depositing a first fill material on the first portion of the silicon nitride layer and into the one or more first gaps;
• planarizing a top surface of the first portion of the silicon nitride layer such that the first fill material within the one or more first gaps is coplanar with the top surface of the first portion of the silicon nitride layer;
• depositing a second portion of the silicon nitride layer such that it extends across the first portion of the silicon nitride layer and across the first fill material disposed within the one or more first gaps;
• selectively removing second regions of the second portion of the silicon nitride layer along the one or more of the dicing lanes to define one or more second gaps between areas of the second portion of the silicon nitride layer;
• depositing a second fill material on the second portion of the silicon nitride layer and into the one or more second gaps;
• planarizing a top surface of the second portion of the silicon nitride layer such that the second fill material within the one or more second gaps is coplanar with the top surface of the second portion of the silicon nitride layer;
• forming one or more additional layers on the top surface of the second portion of the silicon nitride layer;
• and
• forming one or more optical devices on the one or more additional layers.