Surge voltage protection diode and method of forming the same

A method of forming a vertical surge voltage protection diode having a p-n junction formed by first or second and third semiconductor regions, the method comprising the steps of:

• providing the first semiconductor region of a first conductivity type having low resistivity;
• epitaxially growing an epitaxial layer of the first conductivity type on the first semiconductor region;
• and
• forming the second semiconductor region of a second conductivity type having low resistivity in the epitaxial layer by diffusion and heat treatment,
• wherein the third semiconductor region of at least one of the first or second conductivity type region having high resistivity is formed between the first and second semiconductor regions during the heat treatment,
• wherein a depletion layer is formed over the entire third semiconductor region during breakdown voltage when a reverse bias is applied to the p-n junction, and
• wherein the average electric field intensity of the breakdown voltage is ½ or more of the maximum electric field intensity.