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Process development of III-V-based infrared detectors

Time: Wed 2024-03-13 13.00

Location: Electrum, Sal C, Kistagången 16

Language: English

Subject area: Information and Communication Technology

Doctoral student: David Ramos Santesmases , Elektronik och inbyggda system

Opponent: Professor Sanjay Krishna, Ohio State University, Columbus, OH, USA

Supervisor: Associate Professor Per-Erik Hellström, Elektronik och inbyggda system

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QC 20240221


Type-II Superlattice (T2SL) detectors have revolutionized the field of infraredimaging, establishing themselves as the forefront technology in defense, space,and industrial applications. These detectors enable larger formats and higheroperating temperatures (HOT) that minimize the need for bulky and energyconsumingcryogenic cooling, paving the way for imaging systems with reducedSize, Weight, and Power (SWaP).Their versatility across various IR wavebands—long-wavelength, midwavelength,and extended short-wavelength—combined with the intrinsicscalability characteristic of III-V detectors, positions T2SL technology as the idealchoice for next-generation HOT and high-resolution (HD) detectors.This thesis focuses on improving the manufacturing process for T2SL arrays toreduce surface leakage currents induced during pixel etching. This challengebecomes more pronounced with smaller pixels and directly affects the maximumoperating temperature.The investigation into T2SL detector performance provides comprehensiveinsights into the detectors' electrical characteristics. This includes 1/f noiseanalysis and a detailed experimental and quantitative modeling of surface leakagecurrents, proposing strategies for their reduction. Furthermore, the study delvesinto light-matter interactions within focal plane arrays (FPAs) to describe opticalconcentration effects to increase the sensitivity and provides Modulation transferfunction measurements and simulations to discuss the resolution of T2SL arrays.Employing diverse Sb-based T2SL detector photodiode structures, this thesisreports significant progress in the fabrication process, leading to remarkableachievements. These include the demonstration and industrial production of a640 × 512 – 15 μm format FPA operating at 150 K; the production of 10, 7.5,and 5 μm pitch arrays, all capable of functioning at 150 K; and the demonstrationof small-pitch HD FPAs, with the capability of operating at 150K.