Reliability Issues in SiGe HBTs Fabricated on CMOS-Compatible Thin-Film SOI

A comprehensive investigation of reliability issues in both fully-depleted and partially-depleted SiGe HBTs-on-SOI is presented. The devices were subjected to "mixed-mode" stress at 300 K and at 77 K, and the changes in base current I_B, collector resistance R_c , M-1, and AC performance were analyzed. A comparison of mixed-mode stress to conventional reverse EB bias stress is also made, and significant differences are observed. The thermal resistance R_th of the devices is extracted over the 50 K - 300 K range