Integration of an auxiliary device with a clamping device in a transient voltage suppressor

A method of making a transient voltage suppressor (TVS), the method comprising:

• a) providing at least one TVS clamping element;
• and
• b) providing at least one auxiliary device connected to the TVS clamping element;
• wherein the TVS clamping element and the auxiliary device are monolithically fabricated in a structure comprising:
• i) a first epitaxial layer disposed on a substrate,
• ii) a second epitaxial layer disposed on the first epitaxial layer and having a first interface therebetween and
• iii) a third epitaxial layer disposed on the second epitaxial layer and having a second interface therebetween, wherein the second and third epitaxial layers have opposite doping type,
• wherein the TVS clamping element further comprises a first buried structure at the first interface and a second buried structure at the second interface, and wherein thermal processing of the TVS provides a continuous region having doping concentration of 5e16 cm−3 or greater in the TVS clamping element that is formed by diffusion and merging of the first and second buried structures in the second epitaxial layer and by diffusion of the first buried structure to the substrate;
• wherein the auxiliary device includes a p-n junction having a depletion region formed in the second and third epitaxial layers;
• wherein the continuous region extends from a p-n junction of the TVS clamping element to the substrate.