Method of forming a zener diode

A method for forming a zener diode, comprising:

• providing a semiconductor substrate, the semiconductor substrate having a first p-type concentration;
• providing at least one field electrical isolation region;
• providing a mask extending over at least a portion of the at least one field electrical isolation region and extending laterally away from the at least one field electrical isolation region;
• forming a first conductive region in the semiconductor substrate partially aligned with the mask, the first conductive region having a second p-type concentration;
• forming a second conductive region in the semiconductor substrate partially aligned with the mask, the second conductive region have a first n-type concentration, the second conductive region in contact with and above the first conductive region;
• and
• forming a third conductive region in the semiconductor substrate partially aligned with the mask, the third conductive region having a second n-type concentration, the second conductive region in contact with and above the third conductive region;
• the first conductive region, the second conductive region and the third conductive region all having a common vertical alignment with one another in response to partial alignment with the mask and all spaced apart from the at least one field electrical isolation region in response to presence of the mask during formation of the first conductive region, the second conductive region and the third conductive region.