Integration of SiGe NPN devices with tunable collector profiles using a single mask

An alternate local collector masking scheme is demonstrated in 0.18 mum SiGe BiCMOS technology. The method relies on a resist post in the emitter window to create a set of tunable breakdown devices with a single masking step. In initial experiments we have produced a continuum of devices with f_T between 31 and 74 GHz. The f_T times BV_CEO product and f_MAX of these devices is comparable to those produced with traditional local collector implementation. The method could be combined with a collector-doping scalable model to provide additional design flexibility with minimal manufacturing costs. TCAD simulations are employed to study the use of high energies and tilt angle implants to partially penetrate the LC resist post over the emitter window. This alternative relaxes the lithography requirements of the LC post and supports its use with smaller emitter geometries.