Hybrid Sensor Technology (HST) combines the quantum efficiency benefits of CCD devices with the
analog and digital signal processing capabilities of CMOS devices. The CCD is used to collect and
convert photons into electrons in potential wells, in the same manner as conventional CCDs. The
CCD can be either front or back-illuminated, giving the benefit of much higher sensitivities than
traditional CMOS devices. The charge from each pixel is transferred through vertical and then
horizontal shift registers, as with a conventional CCD. However, this is where the similarities with
traditional CCDs end. Patented technology, replaces the need for the CCD to have an on-chip
amplifier, instead the charge is transferred through a unique “bump-bonding” technique from the
CCD silicon to a CMOS silicon chip, as illustrated in figure 1. Once transferred, the charge is amplified
by a very low noise charge amplifier. The CMOS amplifier is operated at KHz speeds to attain the
very low noise performance, however, because the CCD can be divided into many sub-regions,
each with its own output connected to a separate CMOS amplifier circuit, and all these outputs can
be operated in parallel, the net effect provides an extremely high net charge throug