High Res TIFF (2.6 MB)

Thinned Delta-Doped CCD

This is a thinned, delta-doped Charged Coupled Device - CCD. The word you see is a partial reflection of "Spectroscopy." It reads backwards because it is reflected by the mirror-like surface of the chip. The word is not intended as an identification mark, but was used as an indication that the chemically-thinned silicon surface is very flat. This is important, because the CCD is an optical detector, and a high quality, specular surface is important to image quality.

The face down side of the chip that you don't see has the CCD gate and readout structure, and bond pads that are connected to the pins you see at the edge of the package. The silicon itself is only about 10 microns thick (about 1/10 the diameter of a human hair), and the surface is flat because the CCD was bonded to a support structure before thinning. Thinning was done using special equipment at the JPL Microdevices Laboratory.

Following thinning, a few atomic layers of highly-doped silicon are grown on the mirror-like surface, resulting in a remarkable improvement of sensitivity. This CCD can detect light from the x-ray, extreme ultraviolet, near ultraviolet, visible and near infrared regions of the electromagnetic spectrum with high efficiency. It can also detect electrons, protons and ions at lower energies than any other silicon detector.