2D-doped silicon detectors for UV/optical/NIR and x-ray astronomy

Abstract

In this paper we review the physics and performance of back-illuminated CCDs. Models of back-illuminated CCDs are used to derive requirements for stable, strong surface passivation in space-relevant environments. Models and data are used to compare state-of-the-art surface passivation methods with 2D-doped surfaces. MBE growth of 2D-doped silicon on back-illuminated CCDs and CMOS image sensors enables near 100% charge collection efficiency with exceptional stability in space and other harsh environments. Lifetime tests performed on 2D-doped CMOS image sensors using pulsed DUV lasers have demonstrated the unique stability of 2D-doped detectors against high levels of radiation-induced surface damage. The insensitivity of 2D-doped detectors to Si-SiO2 traps has facilitated the development of a variety of coatings and filters with science-enabling capabilities for NASA instruments and missions in the far and near ultraviolet spectral range. We discuss the status and goals of a strategic partnership between JPL and Teledyne e2v for the certification of 2Ddoping processes, and report initial results from our collaboration.

The effect of antireflection coating on the characteristics of wideband silicon avalanche photodetectors

“…Researchers from various countries have adopted methods such as doping, surface treatment, fluorescent material conversion, heterojunction, etc [1][2][3][4] to achieve wide spectral response from ultraviolet to near-infrared, but there is still room for further improvement in responsiveness and wavelength expansion. In addition to designing the structure of the silicon detector, the antireflection coating has a significant effect on response enhancement.…”

Surface Passivation by Quantum Exclusion: On the Quantum Efficiency and Stability of Delta-Doped CCDs and CMOS Image Sensors in Space

“…In Figure 2 , we’ve plotted the QE of the same ion-implanted detector over a spectral range spanning extreme to near UV wavelengths. For comparison, we’ve plotted the reflection-limited QE of silicon detectors over this spectral range, together with the QE of a delta-doped CCD201 detector measured at Open University [ 41 ]. The delta-doped CCDs used in these experiments were developed in a collaboration between JPL and Teledyne e2v for the qualification of high-performance UV detectors for spaceflight.…”

“…In these tests, CMOS image sensors passivated with a delta-doped superlattice were periodically measured during months-long, continuous exposure to high-intensity, pulsed, deep UV lasers at 193nm and 263 nm. Surface damage levels under these conditions were measured to be in the range of 10 14 cm −2 , and yet characterization of the detectors before, during, and after exposure showed that the QE remained stable to within 1% [ 25 , 41 ]. The uniqueness of this stability is highlighted by independent studies of the degradation behavior and damage mechanisms in CCD image sensors exposed to deep UV radiation [ 43 , 44 ].…”

“…For comparison, delta-doped CCD QE data are plotted over the same spectral range, along with the reflection-limited QE (silicon transmittance). All QE measurements were performed by Open University [ 40 , 41 , 42 ].…”

“…Differences between the measured and calculated QE are attributed to quantum transport in the MBE-grown silicon layer (see Section 3.3.3 ). QE data in this Figure were published in Reference [ 41 ] and are also plotted in Figure 2 .…”