Isolated zener diode, an integrated circuit incorporating multiple instances of the zener diode, a method of forming the zener diode and a design structure for the zener diode

A method of forming a diode, said method comprising:

• forming adjacent well regions in a semiconductor layer, said adjacent well regions comprising:
• a first well region, having a first type conductivity, in a semiconductor layer;
• a second well region, having a second type conductivity different from said first type conductivity, in said semiconductor layer and positioned laterally adjacent to and abutting said first well region at an interface;
• forming contact regions and an isolation region,
• said contact regions comprising:
• a first contact region, having said first type conductivity, at a top surface of said semiconductor layer within said first well region;
• and
• a second contact region, having said second type conductivity, at said top surface of said semiconductor layer traversing said interface such that a first end of said second contact region extends laterally into said first well region and a second end of said second contact region extends laterally into said second well region;
• and
• said isolation region at said top surface of said semiconductor layer within said first well region, and positioned laterally between said first contact region and said first end of said second contact region;
• and
• forming a conductive field plate on said isolation region within said first well region and further extending laterally onto said first end of said second contact region within said first well region such that said conductive field plate has a first sidewall aligned above said isolation region and a second sidewall opposite said first sidewall, aligned above said first end of said second contact region within said first well region and offset from said interface so that said conductive field plate covers less than all of said first end of said second contact region within said first well region.

A method of forming a diode, said method comprising:

• forming adjacent well regions in a semiconductor layer, said adjacent well regions comprising:
• a first well region, having a first type conductivity;
• and a second well region, having a second type conductivity different from said first type conductivity, said second well region being positioned laterally adjacent to and abutting said first well region at an interface;
• and
• forming contact regions and at least one isolation region at a top surface of said semiconductor layer such that a first contact region, having said first type conductivity, is positioned within said first well region, such that a second contact region, having said second type conductivity, traverses said interface with a first end extending laterally into said first well region and a second end extending laterally into said second well region, and such that an isolation region is positioned within said first well region between said first contact region and said first end of said second contact region,
• said forming of said contact regions and said at least one isolation region comprising selectively adjusting a length of said first end of said second contact region from said interface to said isolation region so as to selectively adjust a reverse-bias breakdown voltage of said diode.