A comparison of pnp and npn SiGe HBTs fabricated by Ge implantation

Abstract

A study is made of npn and pnp SiGe HBTs produced using Ge implantation. The Ge is implanted into a complementary bipolar process after active area definition. Increased collector currents are observed in both npn and pnp transistors due to the presence of the Ge. The implanted Ge has opposing effects on the emitter dopant diffusion: increasing the arsenic diffusion coefficient in the npn devices and decreasing the boron diffusion coefficient in the pnp devices