Phototransistors for CMOS Optoelectronic Integrated Circuits

Integrated pnp phototransistors (PT) built in 0.6 μm OPTO ASIC CMOS are presented. The production starts with a low doped epitaxial wafer as bulk material. This work presents several different types of phototransistors due to the realization of base and emitter areas. The different types are optimized for different goals, e.g. responsivity or bandwidth. Responsivities up to 76 A/W, 35 A/W for DC light at 675 nm and 850 nm, respectively, as well as 37.2 A/W for modulated light at 300 kHz and 850 nm wavelength were achieved. On the other hand bandwidths up to 14 MHz with lower responsivity were achieved with different design of base and emitter area. Due to the fact that the used process is a production silicon CMOS technology, cheap integration of an integrated optoelectronic circuit is possible. Possible applications are low cost, highly sensitive optical receivers, optical sensors, systems-on-a-chip for optical distance measurement or combined to an array even a 3D camera.