Abstract: A new complementary interface charge island structure of SOI high voltage device (CNI SOI) and its model are presented. CNI SOI is characterized by equidistant high concentration n ⁺ -regions on the top and bottom interfaces of dielectric buried layers. When a high voltage is applied to the device, complementary hole and electron islands are formed on the two n ⁺ -regions on the top and bottom interfaces. The introduced interface charges effectively increase the electric field of the dielectric buried layer (E_I) and reduce the electric field of the silicon layer (E_S), which result in a high breakdown voltage (BV). The influence of structure parameters and its physical mechanism on breakdown voltage are investigated for CNI SOI. E_I = 731 V/μm and BV = 750 V are obtained by 2D simulation on a 1-μm-thick dielectric layer and 5-μm-thick top silicon layer. Moreover, enhanced field E_I and reduced field E_S by the accumulated interface charges reach 641.3 V/μm and 23.73 V/μm, respectively.

Key words: Complement, Charge islands, Interface charges, Dielectric buried layer, Breakdown voltage