High-endurance solar-blind photodetectors using AlN on Si substrates for extreme harsh environment applications

摘要

This work demonstrates the high-temperature and high speed operation of solar-blind deep ultraviolet (DUV) metal-semiconductor-metal (MSM) Schottky photodectors (PDs) up to 300°C using AlN thin films on Si(100) substrates. For 2-MeV proton irradiation, the photocurrent-to-dark-current ratio (PDCR) value of AlN MSM PDs is 0.7 under a 5 V bias at proton fluences up to 10~(13) cm~(-2), enabling highly specific DUV detection in radiation-intense space applications. The use of AlN MSM DUV PDs in harsh environments with high endurance/reliability suitably manufactured by VLSI technology is the breakthrough in Si-based device development. As shown in TABLE I, AlN with direct bandgap (～6.2 eV), high thermal conductivity (3.2 W/cm°C), high breakdown field (4-6 MV/cm), excellent thermal stability as well as radiation hardness is an ideal candidate for the development of solar-blind DUV PDs in harsh environment applications [1,2]. So far, conventional AlN-based epitaxial layers were grown either on sapphire or on SiC substrates, leading to the high substrate cost. In this study, we demonstrate solar-blind Schottky PDs with back-to-back MSM geometry by employing AlN thin films on Si(100) substrates using the reactive sputtering deposition for use in harsh environments.