Complementary bipolar processes on bonded SOI

Bipolar transistors are well suited to analog circuits due to their exponential properties and their ability to drive capacitive loads. Analog Devices´ first complementary bipolar (CB) process used junction isolation. During the development phase of the second generation CB process it was decided that we employ bonded wafers with trenches to achieve full dielectric isolation. That process has been running in production since 1992 and has more than 100 products being built on it. Subsequent generations of CB processes at Analog have continued to use this isolation approach. In this paper we discuss the merits of using bonded SOI versus standard junction isolation for our processes. We describe the processes and their performance, as well as the challenges encountered in the development of the processes due to the incorporation of bonded wafer starting material