Photoelectric properties of MIS structures on high-resistivity p-type silicon with aluminium nitride tunnelling insulator

Abstract

Photoelectric properties of MIS tunnel diodes produced on high-resistive p-type silicon wafers with thin aluminium nitride AlN insulator layer and Pd or Al metal gate electrodes were investigated. It was found that synthesized AlN films possess a fixed positive charge, which leads to the creation of near-surface inversion layer in silicon substrate. The ratio of the photocurrent to the dark current K = Iph / Idark (on / off ratio) was found to depend on the gate electrode material, illumination intensity and the applied reverse bias. For studied MIS structures K ratio varied from 10 4 to 10 5 and was two orders of magnitude higher than that for the control MS structure without the insulator layer. High on / off ratio of such MIS structures with AlN tunnelling insulator promotes their application as an effective photodetectors in optoelectronics.

Current-voltage simulation analysis of MIS structure utilizing aluminium nitride on high resistivity silicon

“…Figure 2 illustrates the dark current comparison between the simulated work and the experimental work obtained from [4] for MS structure as shown in Figure 1(a). Based on the figure, it can be seen that the I-V curve for simulated work shows a linear trend and is symmetrical at accumulation and inversion biases (denoted by negative and positive voltages, respectively), indicating ohmic behaviour of the MS interface.…”

“…The MS and MIS photodetector structures are identical to the structures proposed and fabricated in [4] and the illustration of the cross-sectional layers for both structures are as shown in Figure 1 below. In both structures, Palladium (Pd) and p-type high resistivity silicon with resistivity of 4200 Ω.cm is used as metal contacts and semiconductor substrates, respectively.…”

“…In Figure 1(b), AlN with thickness of 2 nm is incorporated as the thin insulating layer. These structures are built and simulated using TCAD simulation tools, and the their respective I-V characteristics are analysed and compared with the experimental results reported by [4]. Next, structure simulated in Figure 1(b) is used as the basis of further analysis involving AlN tunneling insulator.…”

“…The incorporation of high resistivity substrate in the MIS structure can actually provide better bias response, in which deeper depletion region is created and inversion of charges is achieved at much lower bias voltage [3]. Due to these reasons, Bazlov et al has taken interest in experimenting with MIS structure on high resistivity silicon substrate [4]. In his work, aluminium nitride (AlN) is utilized as the thin insulating layer due to its low-temperature deposition process [5] and excellent electrical, thermal and optical properties [6,7].…”

“…In this work, the effects of varying the AlN thickness on MIS structure based on high resistivity silicon will be discussed via current-voltage (I-V) simulation analysis. First, the MS and MIS structures used in [4] are simulated and modelled empirically to ensure correct representations of high resistivity silicon substrate and AlN insulating materials. Then, direct comparison in terms of dark currents and photo currents when using low resistivity silicon and high resistivity silicon are analyzed.…”