The Rule of Field Enhancement for Buried Dielectric Layer of SOI High Voltage Devices

Based on the concept of critical field E_I,C approaching for dielectric layer, the ENDIF (ENhanced Dielectric layer Field) principle for SOI HV devices is proposed for the first time, from which three approaches to enhance field of dielectric layer E_I for increasing vertical breakdown voltage V_B,v are presented: (1) enhance the critical field in silicon E_S,C at the interface of Si/dielectric layer by using thin silicon layer. Considering the threshold energy of silicon E_T, the expression of E_S,C for both thick and thin Si layer is derived firstly and shown that E_S,C increases sharply with decreasing of thin Si layer thickness t_s and E_S,C and E_I for SiO₂ are up to 141V /mum and 422 V /mum at t_s = 0.1mum, respectively; (2) raise a structure of buried dielectrics layer with low permittivity (LK) and variable permittivity (VK) (3) implement the interface charges between silicon and dielectric layer, from which a new dielectric structure with DT SOI is proposed, and E_I of 300 V/mum is experimentally obtained. By ENDIF, the formula E_I and V_B,V are given, which are meet good with 2D simulation and experimental results. With ENDIF, several conventional SOI devices are well explained.