Methods and systems for fabrication of infrared transparent window wafer with integrated anti-reflection grating structures

A method of fabricating a focal plane array (FPA) structure, the method comprising:

• providing a handle wafer having a first surface and a second surface opposite the first surface;
• providing a device wafer including a single crystalline silicon layer disposed on an oxide layer, the single crystalline silicon layer having a planar side and the oxide layer having a bonding side that is opposite the planar side;
• forming anti-reflection (AR) grating structures in a first portion of the first surface and a second portion of the second surface of the handle wafer;
• bonding the bonding side of the oxide layer to the first surface of the handle wafer;
• and
• etching a recess in the planar side of the single crystal silicon layer to:
• remove the oxide layer;
• form a plurality of recess walls;
• and
• expose the AR grating structures in the first portion of the first surface of the handle wafer.

A method of fabricating a focal plane array (FPA) structure, the method comprising:

• providing a handle wafer having a first surface and a second surface opposite the first surface;
• providing a device wafer including a single crystal silicon layer disposed on an oxide layer, the single crystal silicon layer having a planar side and the oxide layer having a bonding side that is opposite the planar side;
• forming first anti-reflection (AR) grating structures in a first portion of the first surface of the handle wafer;
• bonding the bonding side of the oxide layer to the first surface of the handle wafer;
• forming second AR grating structures in a second portion of the second surface of the handle wafer;
• and
• etching a recess in the planar side of the single crystal silicon layer to:
• remove the oxide layer;
• form a plurality of recess walls;
• and
• expose the first AR grating structures in the first portion of the first surface of the handle wafer.