MTF Comparisons Between Mesa and Planar Focal Plane Detector Structures

摘要

Raytheon Vision Systems (RVS) has developed scanning, high-speed (＞3klps), all digital, with on-chip Analog-to-Digital Conversion (ADC), mid-wave infrared (MWIR 3-5μm) focal plane arrays (FPA) with excellent modulation transfer function (MTF) performance. Using secondary ion mass spectrometry (SIMS) data and detailed models of the mesa geometry, RVS modeled the predicted detector MTF performance of detectors. These detectors have a mesa structure and geometry for improved MTF performance compared to planar HgCdTe and InSb detector structures and other similar detector structures such as nBn. Figure 1 compares the modeled data to measured MTF data obtained from edge spread measurements and shows excellent agreement. The measured data was obtained using an advanced, Raytheon developed test set with 1 urn precision alignment and automatic data acquisition for report generation in less than five minutes per FPA. The measured MTF values of 83 unique parts, Figure 2, had a standard deviation of 0.0094 and a mean absolute deviation of 0.0066 at Nyquist frequency (0.5 cycles per pixel), showing excellent process repeatability and a design that supports high MTF with good repeatability.