Method for liquid-phase thin film epitaxy

A process of liquid-phase epitaxy, comprising:

• heating a plurality of substrates mounted in boats within an interior of a main furnace by maintaining the main furnace at a first temperature level within a first temperature range of 700.degree. to 800.degree. C. while maintaining within said interior a first auxiliary furnace surrounding the boats and a first melt of gallium arsenide, aluminum and zinc and a second auxiliary furnace surrounding the boats and a second melt of gallium arsenide and a chalcogenide at a second temperature level within a second temperature range of 750.degree. to 900.degree. C.;
• sliding one surface of a first one of said substrates into contact with said first melt to form a first epitaxial layer of gallium aluminum arsenide on the one surface of said first substrate while reducing the temperature of said first auxiliary furnace and maintaining said main furnace within said first temperature range and said second auxiliary furnace within said second temperature range;
• sliding said one surface of said first one of said substrates from contact with said first melt and raising the temperature of said first auxiliary furnace to said second temperature level;
• sliding said one surface of said first one of said substrates into contact with said second melt to form a second epitaxial layer of gallium arsenide on the one surface of said first substrate and sliding one surface of said second one of said substrates into contact with said first melt to form a first epitaxial layer of gallium aluminum arsenide on the one surface of said second substrate, while reducing the temperatures of said first and second auxiliary furnaces;
• simultaneously sliding said one surface of said first substrate from contact with said second melt and sliding said one surface of said second substrate out of contact with said first melt and raising the temperature of said first and second auxiliary furnaces to said second temperature level;
• sliding said one surface of said second one of said substrates into contact with said second melt to form a second epitaxial layer of gallium arsenide on the one surface of said second substrate while reducing the temperature of said second auxiliary furnace;
• and
• sliding said one surface of said second substrate out of contact with said second melt.

A process of liquid-phase epitaxy, comprising:

• heating a plurality of substrates within the interior of a main furnace by maintaining the main furnace at a first temperature level within a first temperature range while maintaining within said interior a first auxiliary furnace surrounding a first semiconductor melt and a path of the substrates adjacent to the first semiconductor melt, and a second auxiliary furnace surrounding a second semiconductor melt and a path of the substrates adjacent to the second semiconductor melt, at second temperature levels within a second temperature range;
• placing one surface of a first one of said substrates into contact with said first melt to form a first epitaxial layer on the one surface of said first substrate while reducing the temperature of said first auxiliary furnace;
• removing said one surface of said first one of said substrates out of contact with said first melt and raising the temperature of said first auxiliary furnace to one of said second temperature levels;
• placing said one surface of said first one of said substrates into contact with said second melt to form a second epitaxial layer on the first epitaxial layer of said first substrate and placing one surface of said second one of said substrates into contact with said first melt to form a first epitaxial layer on the one surface of said second substrate, while reducing the temperatures of said first and second auxiliary furnaces;
• simultaneously removing said first and second substrates from contact with said first and second melts;
• raising the temperatures of said first and second auxiliary furnaces to said second temperature levels;
• placing said first epitaxial layer of said second substrate into contact with said second melt while reducing the temperature of said second auxiliary furnace;
• and
• removing said second substrate from contact with said second melt.

A process of liquid-phase epitaxy, comprising:

• heating a main furnace having an interior capable of receiving a plurality of boats bearing semiconductor substrates and a plurality of semiconductor melts, to a first temperature level within a first temperature range while heating a plurality of auxiliary furnaces surrounding the boats and corresponding different ones of said semiconductor melts to second temperature levels within a second temperature range to maintain the corresponding ones of said semiconductor melts in molten states, said second temperature range being greater than said first temperature level;
• placing a first one of said substrates into contact with a first one of said melts to form a first epitaxial layer on the first substrate while reducing the temperature of a corresponding auxiliary furnace to enable growth of said first epitaxial layer;
• removing said first one of said substrates from contact with said first one of said melts and raising the temperature of the auxiliary furnace corresponding to said first one of said melts to said second temperature range;
• forming one of a second epitaxial layer on a first epitaxial layer of said first substrate and a first epitaxial layer on said second substrate by placing one of said first epitaxial layer of said first substrate in contact with said second melt while reducing the temperature of said second auxiliary furnace to enable formation of a second epitaxial layer on said first epitaxial layer of said first substrate and one surface of said second substrate in contact with said first melt while reducing the temperature of said first auxiliary furnace to enable formation of a first epitaxial layer on said first substrate;
• forming the other of said second epitaxial layer on said first epitaxial layer of said first substrate and the first epitaxial layer on said second substrate by placing the other of said first epitaxial layer of said first substrate in contact with said second melt while reducing the temperature of said second auxiliary furnace to enable formation of the second epitaxial layer on said first epitaxial layer of said first substrate and the one surface of said second substrate in contact with said first melt while reducing the temperature of said first auxiliary formation of the first epitaxial layer on said first substrate;
• and
• removing said first and second substrates from contact with said first and second melts after formation of said first epitaxial layer on said first substrate.

A process for liquid phase epitaxy, comprising:

• maintaining an interior of a main furnace within a first temperature range;
• heating within said interior, to a second temperature level within a second temperature range sufficient to make a first liquid melt of gallium arsenide, aluminum and zinc, said first melt and a first volume of said interior adjoining the first melt and occupied by successive ones of a plurality of substrates as the substrates travel along a path adjacent to the first melt through said interior, by using a first auxiliary furnace surrounding the first melt and the first volume;
• forming a first epitaxial layer on a first substrate by sliding said first substrate into said first volume and contact with said first liquid melt and reducing said first melt to a third temperature level;
• separating said first substrate from said first melt by sliding said first substrate from said first volume after forming said first epitaxial layer;
• heating said first melt with said first auxiliary furnace to said second temperature level;
• heating within said interior, to a fourth temperature level within said second temperature range sufficient to make a second liquid melt of gallium arsenide and a chalcogenide, said second melt and a second volume of said interior adjoining the second melt and occupied by successive ones of said plurality of substrates as the substrates travel along a path adjacent to the second melt through said interior, by using a second auxiliary furnace surrounding the second melt and the second volume;
• and
• forming a second epitaxial layer on a first epitaxial layer of said first substrate and a first epitaxial layer on said second substrate, by sliding said first substrate into said second volume and contact with said second melt and reducing said second melt to a fifth temperature level, and by sliding said second substrate into said first volume and contact with said first melt and reducing said first melt to said third temperature level.

A process for liquid phase epitaxy, comprising:

• maintaining an interior of a main furnace within a first temperature range;
• heating within said interior, to a second temperature level within a second temperature range sufficient to make a first liquid melt of a semiconducting material and impurities, said first melt and a first volume of said interior adjoining the first melt and occupied by successive ones of a plurality of substrates as the substrates travel along a path adjacent to the first melt through said interior, by using a first auxiliary furnace surrounding the first melt and the first volume;
• forming a first epitaxial layer on a first substrate by sliding said first substrate into said first volume and contact with said first liquid melt and reducing said first melt to a third temperature level;
• separating said first substrate from said first melt by sliding said first substrate from said first volume after forming said first epitaxial layer;
• heating said first melt with said first auxiliary furnace to said second temperature level;
• heating within said interior, to a fourth temperature level within said second temperature range sufficient to make a second liquid melt of a semiconducting material and impurities, said second melt and a second volume of said interior adjoining the first melt and occupied by successive ones of a plurality of substrates as the substrates travel along a path adjacent to the first melt through said interior, by using a second auxiliary furnace surrounding the second melt and the second volume;
• forming a second epitaxial layer on said first epitaxial layer of said first substrate and a first epitaxial layer on said second substrate, by sliding said first substrate into said second volume and contact with said second melt and reducing said second melt to a fifth temperature level, and by sliding a second substrate into said first volume and contact with said first melt and reducing said first melt to said third temperature level.