What is an SOI?

SOI stands for Silicon-On-Insulator.

Typically, pn junction isolation is used to electrically isolate devices on an integrated circuit (IC). In contrast, SOI uses a silicon dioxide (SiO2) layer for isolation between devices. SOI technology makes it possible to prevent malfunction and destruction of an IC caused by vertical and horizontal parasitic devices formed by conventional pn junction isolation.

Figure 1 Cross-sectional view of an SOI structure
Figure 1 Cross-sectional view of an SOI structure
Figure 2 Cross-sectional view of  p-n junction isolation
Figure 2 Cross-sectional view of p-n junction isolation

For High-voltage IPD’s SOI, please refer to "High voltage intelligent power device application note"