High-efficiency UV/optical/NIR detectors for large aperture telescopes and UV explorer missions: development of and field observations with delta-doped arrays

Abstract

A number of exciting concepts are under development for Flagship, Probe class, Explorer class, and Suborbital class NASA missions in the ultraviolet/optical spectral ranges. These missions will depend on high performance silicon detector arrays being delivered affordably and in high numbers. In a focused effort we have advanced delta-doping technology to high throughput and high yield wafer-scale processing, encompassing a multitude of state-of-the-art silicon-based detector formats and designs. As part of this technology advancement and in preparation for upcoming missions, we have embarked on a number of field observations, instrument integrations, and independent evaluations of delta-doped arrays. In this paper, we present recent data and innovations from the Advanced Detectors and Systems program at JPL, including two-dimensional doping technology; our end-to-end postfabrication processing of high performance UV/Optical/NIR arrays; and advanced coatings for detectors and optical elements. Additionally, we present examples of past, in-progress, and planned observations and deployments of deltadoped arrays.

Atomic Layer Deposition of Lithium Fluoride Optical Coatings for the Ultraviolet

“…Previous work in our lab has explored the ALD of MgF 2 and AlF 3 for the same UV applications, utilizing anhydrous HF as the fluorine-containing precursor [17,18]. We have also produced preliminary FUV mirror results for Al protected with these materials [19,20] and multilayer filter stacks comprised of Al and metal fluorides for FUV detector-integrated filters [21]. In this work, we expand this anhydrous HF approach to the deposition of LiF and assess the morphology, composition, and optical properties of the resulting thin films.…”

The FIREBall-2 UV balloon telescope: 2018 flight and improvements for 2020

“…It has a line density of 2400 lines/mm and angle of incidence of 28 • . 24 The FB-2 UV EMCCD is provided by the Microdevices Laboratory (MDL) at JPL (PI: S. Nikzad [25][26][27] ) as a part of the FB-2 collaboration. A Teledyne e2v CCD201-20 wafer is thinned and δ-doped using a molecular-beam epitaxy, which grows a single layer of boron-doped silicon.…”

“…A Teledyne e2v CCD201-20 wafer is thinned and δ-doped using a molecular-beam epitaxy, which grows a single layer of boron-doped silicon. 26 This process significantly increases the quantum efficiency (QE) of the device. An AR coating is added at the end of the process to overcome QE limitations due to the reflectivity of the silicon.…”

Materials and process development for the fabrication of far ultraviolet device-integrated filters for visible-blind Si sensors

“…8,24,25 This fast scintillation component at 220 nm has potential applications in high rate particle physics calorimetry experiments, but BaF 2 also produces a larger, slower scintillation component at 300 nm. In order to achieve high detection rates, readout devices must therefore suppress this component while maintaining high sensitivity at 220 nm.…”

“…When operating at high gain the depletion conditions are distinctly different, and the projected 'effective' QE is higher than that measured at unity gain. 25 In this sense, the 70% scaling factor represents a lower limit to the internal QE of the device and/or the relative transmission of the MDDIF structure. Nevertheless, improvements over previous demonstrations are clear, primarily resulting from reductions in the cumulative thermal budget experienced by the MDDIF structure during processing.…”