Influence of transient enhanced diffusion of the intrinsic base dopant profile on SiGeHBT DC and HF characteristics

The influence of transient enhanced boron out-diffusion from the intrinsic base, caused by excess silicon interstitials created during the extrinsic b ase implantation, has been investigated for a non-selective SiGe HBT proces s. Devices with different designs of the extrinsic base region were fabrica ted, where some designs allowed part of the epitaxial base to be implanted with a high boron dose, hereby increasing the number of silicon interstitia ls close to the intrinsic device. These devices showed a marked degradation of DC characteristics and HF performance. 2D-device simulations were used to investigate the sensitivity in DC and HF parameters to vertical base pro file changes. Good agreement was obtained between measured and simulated DC and HF characteristics. (C) 2000 Published by Elsevier Science Ltd. Ail ri ghts reserved.