Charge Quantizing CCDs Optimized for Astronomy

针对天文学优化的电荷量化 CCD

• 批准号: 2308380
• 负责人: Roger Smith
• 金额: $ 148.26万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2026-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2308380&HistoricalAwards=false
• 关键词: Charge; Quantizing; CCDs; Optimized; Astronomy

Spectroscopy is a key tool used in many branches of science and industry. Light emitted in specific colors can identify the elements present, their relative concentration, temperature or even the velocity of the source. However, the signals are weak, and the electrical noise added by the sensor itself can limit what can be measured. This electrical noise cannot be eliminated, but in sensors called “Charge Couple Devices” (CCD) the electrical charge generated by the signal can be measured many times and averaged until the exact number of electrons in the pixel is determined. Unfortunately, this technique greatly increases the time to readout a complete image. This team will demonstrate the ability to readout an image in a few minutes instead of hours. The image sensor will be designed by the vendor Semiconductor Technology Associates (STA) to have 4096x4096 pixels, with several hundred optimized outputs operating in parallel. Caltech will develop compact electronics located near the sensor to digitize the many output signals. These sensors will be manufactured at Microchip Technology silicon foundry in Arizona and will subsequently become commercially available. These CCDs will typically improve the sensitivity of spectrographs used in astronomy by a factor of two to four. Similar gains will be possible in low light applications in chemistry, biology, and medicine. Caltech will involve undergraduate students in the testing of electronics and detectors.This team will produce an n-channel Quantizing CCD (qCCD) in a commonly used 4K x 4K format (split frame transfer) with 128 floating gate amplifiers per extended serial register. A new differential version of the standard Floating Gate Amplifier (FGA) will halve the readout time for any given channel count and pixel sampling rate. The Differential FGA output will first be optimized in numerical simulations using a commercial software package from SILVACO and then validated by testing a range of transistor geometries and doping profiles. A new mounting package to support the high pin count will connect by flex circuit to a compact electronics module designed to support 128 differential channels. This will perform digital differential averaging close to the detector to greatly reduce the number of signal connections needed through the vacuum wall. The 4K x 4K qCCD will be manufactured using conventional epitaxial n-channel technology at an onshore foundry. The move from traditional 6” wafers to 8” wafers will increase the number of devices per wafer from one to four. Backside processing and thinning will be optimized to maximize UV and blue response. This program will include a demonstration on a new spectrograph being deployed at Palomar Observatory. The creation of a 4Kx 4K blue optimized CCD that achieves charge quantization in under 2 minutes should open a pathway to very significant sensitivity gains at astronomical telescopes. This project will result in large-format image sensor manufacturing in the USA again, and it will promote global competitiveness of USA-based small businesses engaged in semiconductor design and fabrication.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

光谱学是许多科学和工业领域使用的关键工具。以特定颜色发出的光可以识别存在的元素、它们的相对浓度、温度甚至源的速度。但是，信号很弱，并且会增加电噪声。传感器本身的信号可能会限制可测量的范围，但这种电噪声无法消除，但在称为“电荷耦合器件”(CCD) 的传感器中，可以多次测量信号产生的电荷并对其进行平均，直到获得准确的电子数。在像素中确定。不幸的是，这种技术大大增加了读出完整图像的时间。该团队将展示在几分钟而不是几小时内读出图像的能力。图像传感器将由供应商 Semiconductor Technology Associates (STA) 设计为具有 4096x4096。像素，具有数百个并行运行的优化输出，加州理工学院将开发位于传感器附近的紧凑型电子器件，以将许多输出信号数字化。这些传感器将在亚利桑那州的 Microchip Technology 硅铸造厂制造。这些 CCD 通常会将天文学中使用的光谱仪的灵敏度提高两到四倍，在化学、生物学和医学领域的低光应用中也可能获得类似的效果，而加州理工学院将让本科生参与电子测试。该团队将生产一种常用的 4K x 4K 格式（分割帧传输）的 n 通道量化 CCD (qCCD)，每个扩展串行寄存器具有 128 个浮栅放大器。标准浮栅放大器 (FGA) 将使任何给定通道数和像素采样率的读出时间减半。差分 FGA 输出将首先使用 SILVACO 的商业软件包在数值模拟中进行优化，然后通过测试一系列数据进行验证。支持高引脚数的新安装封装将通过柔性电路连接到旨在支持 128 个差分通道的紧凑电子模块，这将在探测器附近执行数字差分平均。 4K x 4K qCCD 将在陆上铸造厂使用传统的外延 n 通道技术制造，从而大大减少通过真空壁所需的信号连接数量。从传统的 6 英寸晶圆转移到 8 英寸晶圆将增加数量。每个晶圆的器件数量从 1 个增加到 4 个，背面处理和减薄将得到优化，以最大限度地提高紫外线和蓝色响应。创建可在 2 分钟内实现电荷量化的 4Kx 4K 蓝色优化 CCD，将为天文望远镜的灵敏度大幅提升开辟一条道路。该项目将再次在美国制造大幅面图像传感器，并将促进全球的发展。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。