Highly sensitive visible-blind extreme ultraviolet Ni/4H-SiC Schottky photodiodes with large detection area

Abstract

Ni/4H-SiC Schottky photodiodes of 5 mm x 5 mm area have been fabricated and characterized. The photodiodes show less than 0.1 pA dark current at -4 V and an ideality factor of 1.06. A quantum efficiency (QE) between 3 and 400 nm has been calibrated and compared with Si photodiodes optimized for extreme ultraviolet (EUV) detection. In the EUV region, the QE of SiC detectors increases from 0.14 electrons/photon at 120 nm to 30 electrons/photon at 3 nm. The mean energy of electron-hole pair generation of 4H-SiC estimated from the spectral QE is found to be 7.9 eV.

Annealing effects on the optical and structural properties of Al2O3/SiO2 films as UV antireflection coatings on 4H-SiC substrates

“…Silicon carbide (SiC)-based ultraviolet (UV) photodetectors such as Schottky barrier [1,2], metal-semiconductor-metal (MSM) [3], p-i-n [4] and avalanche [5,6] have been presenting considerable potential for UV detection in flame detection, ozone-hole sensing, short-range communication, etc. The 4H-SiC p-i-n photodetectors [4] were found to have the peak responsivity of 0.13 A/W and the maximum external quantum efficiency (QE) of 61% at the wavelength of 270 nm.…”

“…The 4H-SiC p-i-n photodetectors [4] were found to have the peak responsivity of 0.13 A/W and the maximum external quantum efficiency (QE) of 61% at the wavelength of 270 nm. The Ni/4H-SiC Schottky photodiodes were reported [2] to have the external QE higher than 50% from 230 to 295 nm and get the peak of 65% at 275 nm, corresponding to an internal QE close to 100%. Therefore, the external QE was especially considered to have much room for improvement.…”

“…Therefore, we deposited Al 2 O 3 /SiO 2 double-layer UV antireflection coatings on 4H-SiC substrates by electron-beam evaporation for the purpose of improving the external QE of 4H-SiC-based UV photodetectors. As annealing is an important postprocessing for forming high quality Schottky and ohmic contacts [2,4] on 4H-SiC substrates, it is significant to examine the optical and structural properties of the Al 2 O 3 /SiO 2 films annealed at various temperatures.…”

Si doping superlattice structure on 6H-SiC(0001)

“…The SAED patterns of the p/n-Si DSL corresponding to Si[011] zone axes are shown in Fig. 2(b), confirming the epitaxial growth of the Si films with [1][2][3][4][5][6][7][8][9][10][11] preferred orientation. Figure 2(c) shows a highresolution TEM image of the p-Si/n-Si interface.…”

“…SiC is a desirable material for power devices due to its superior physical properties such as wide bandgap, high thermal conductivity, and high critical electric field, etc.. [1][2][3] However, because of the wide bandgap, SiCbased photoelectric devices can only be driven by ultraviolet (UV) light, which essentially limit its application for a detection of visible and infrared light. Moreover, UV light is harmful to the human body and is not the conventional light source in optical communications.…”