Double-sided reusable template for fabrication of semiconductor substrates for photovoltaic cell and microelectronics device manufacturing

A method for making a pair of crystalline thin-film semiconductor substrates, said method comprising:

• providing a crystalline semiconductor wafer;
• pre-structuring a first surface and a second surface of said crystalline semiconductor wafer with a random texture or a regular pattern, thereby producing a set of structural surface topography features on said first surface and said second surface, said structural surface topography features comprising a plurality of topography features;
• and
• cleaning said first surface and said second surface of said crystalline semiconductor wafer, said crystalline semiconductor wafer serving as a double-sided reusable template;
• producing a first porous semiconductor layer on said first surface and a second porous semiconductor layer on said second surface of said double-sided reusable template via an anodic etching process, said porous semiconductor layers having a crystallinity consistent with said double-sided reusable template;
• depositing a first crystalline thin-film semiconductor substrate on said first porous semiconductor layer and a second crystalline thin-film semiconductor substrate on said second porous semiconductor layer, said crystalline thin-film semiconductor substrates having a crystallinity consistent with said porous semiconductor layers and said reusable template;
• separating said first and said second monocrystalline thin-film semiconductor substrates from said first and said second porous semiconductor layers.

A method for making a pair of crystalline thin-film silicon substrates, said method comprising:

• providing a crystalline silicon wafer;
• concurrently pre-structuring a first surface and a second surface of said crystalline silicon wafer with a random texture, thereby producing a set of structural surface topography features on said first surface and said second surface, said structural surface topography features comprising a plurality of topography features;
• and
• cleaning said first surface and said second surface of said crystalline silicon wafer, said crystalline silicon wafer serving as a double-sided reusable template;
• producing a first porous silicon layer on said first surface and a second porous silicon layer on said second surface of said double-sided reusable template via an anodic etching process, said porous silicon layers having a crystallinity consistent with said double-sided reusable template;
• depositing a first crystalline thin-film silicon substrate on said first porous silicon layer and a second crystalline thin-film silicon substrate on said second porous silicon layer, said crystalline thin-film silicon substrates having a crystallinity consistent with said porous silicon layers and said reusable template;
• separating said first and said second monocrystalline thin-film semiconductor substrates from said first and said second porous semiconductor layers.

A method for making a pair of monocrystalline thin-film silicon substrates, said method comprising:

• providing a monocrystalline semiconductor wafer;
• pre-structuring a first surface and a second surface of said monocrystalline silicon wafer with a three-dimensional texture, thereby producing a set of structural surface topography features on said first surface and said second surface, said structural surface topography features comprising a plurality of topography features creating a non-planar structure;
• and
• cleaning said first surface and said second surface of said monocrystalline silicon wafer, said monocrystalline silicon wafer serving as a double-sided reusable template;
• producing a first porous silicon layer on said first surface and a second porous silicon layer on said second surface of said double-sided reusable template via an anodic etching process, said porous silicon layers having a crystallinity consistent with said double-sided reusable template;
• epitaxially depositing a first monocrystalline thin-film silicon substrate on said first porous silicon layer and a second monocrystalline thin-film silicon substrate on said second porous silicon layer, said monocrystalline thin-film silicon substrates having a crystallinity consistent with said porous silicon layers and said reusable template;
• separating said first and said second monocrystalline thin-film silicon substrates from said first and said second porous silicon layers.

A method for making a pair of monocrystalline thin-film silicon substrates, said method comprising:

• providing a monocrystalline semiconductor wafer;
• concurrently cleaning said first surface and said second surface of said monocrystalline silicon wafer, said monocrystalline silicon wafer serving as a double-sided reusable template;
• producing a first porous silicon layer on said first surface and a second porous silicon layer on said second surface of said double-sided reusable template via an anodic etching process, said porous silicon layers having a crystallinity consistent with said double-sided reusable template;
• epitaxially depositing a first monocrystalline thin-film silicon substrate on said first porous silicon layer and a second monocrystalline thin-film silicon substrate on said second porous silicon layer, said monocrystalline thin-film silicon substrates having a crystallinity consistent with said porous silicon layers and said reusable template;
• separating said first and said second monocrystalline thin-film silicon substrates from said first and said second porous silicon layers.

An apparatus for forming porous silicon layers on at least two surfaces of a plurality of silicon templates in a batch electrochemical anodic etch process, said apparatus comprising:

• a plurality of edge-sealing template mounts, with a plurality of templates disposed within said mounts, said plurality of mounts operable to prevent formation of porous silicon at said template edges;
• an electrolyte disposed among said plurality of templates;
• an electrolyte temperature controller;
• a gas bubble extractor operable to remove gas bubbles from said plurality of templates by circulating said electrolyte;
• and
• a power supply operable to switch polarity, change current intensity, and control etching time to produce said porous silicon layers.