Semiconductor device with electrically coupled spiral inductors

A coupled inductor structure having a high quality factor, said structure comprising:

• a substrate of semiconductor material, said substrate having a well formed therein;
• at least three substantially spiral inductors formed within said well, said inductors being arranged in said well such that each of said inductors is inductively coupled to at least one other of said inductors;
• and
• a respective pair of input/output terminals for each of said inductors.

A signal splitting and combining circuit comprising:

• a substrate of semiconductor material, said substrate having a well formed therein;
• at least three substantially spiral inductors formed within said well, said inductors being arranged in said well such that each of said inductors is inductively coupled to at least one other of said inductors, a third one of said inductors being coupled between first and second ones of said inductors;
• and
• a respective pair of input/output terminals for each of said inductors;
• wherein:
• when respective first and second signals are input to each of first and second ones of said pairs of input/output terminals, a sum of multiples of said first and second signals is output on a third one of said pairs of input/output terminals;
• and
• when an input signal is input on said third one of said pairs of input/output terminals, respective first and second output signals are output on respective ones of said first and second pairs of input/output terminals, said input signal being a sum of multiples of said first and second output signals.

A method of forming a coupled inductor structure in a semiconductor substrate having a surface, said method comprising:

• forming a well in said surface of said substrate, said well having a bottom and a side wall;
• depositing a first insulating layer on said bottom of said well;
• depositing a first lead-in conductor over said first insulating layer;
• depositing a second insulating layer over said first lead-in conductor;
• depositing a first spiral inductor over said second insulating layer in contact with said first lead-in conductor;
• forming a first termination wire conducting between said first spiral inductor and said surface;
• depositing a third insulating layer over said first spiral inductor;
• depositing a second lead-in conductor over said third insulating layer;
• depositing a fourth insulating layer over said second lead-in conductor;
• depositing a second spiral inductor over said fourth insulating layer in contact with said second lead-in conductor;
• forming a second termination wire conducting between said second spiral inductor and said surface;
• depositing a fifth insulating layer over said second spiral inductor;
• depositing a third lead-in conductor over said fifth insulating layer;
• depositing a sixth insulating layer over said third lead-in conductor;
• depositing a third spiral inductor over said sixth insulating layer in contact with said third lead-in conductor;
• forming a third termination wire conducting between said third spiral inductor and said surface;
• depositing a seventh insulating layer over said third spiral inductor.