Al/nanocrystalline CeOx/Si/Al structures for heterojunction photodetectors

Oleksandr Vasyliovych Borisov,N V Maksimchuk,L N Korolevych

doi:10.20535/2312-1807.2014.19.6.112902

Abstract

A stable metal/nc-CeOx/Si structures were fabricated and investigated for the creation of heterojunction photodetectors. The photosensitivity of obtained structures in the visible range was 330 μA/lm∙V. The value of the interface state density was of 7∙1010 cm-2∙eV-1. DC dielectric constant of nanocrystalline CeOx film was about 15. Thin (80 nm) cerium oxide films in Al/nc-CeOx/Si/Al structures were obtained by the vacuum flash evaporation method. The effect of technological factors on the CeOx films microstructure as well as on photoelectric properties of the Al/nc-CeOx/Si/Al structures has been investigated. Electrophysical and photoelectric properties of the Al/nc-CeOx/Si/Al structures has been investigated. It was revealed that the nanocrystalline CeOx layer in the obtained Al/nc-CeOx/Si/Al structures is a semiconductor with an electronic conductivity. It’s volume resistivity is within the range of 0.5-30 МOhm∙cm. Reference 9, figures 2.

Highlights

Cerium oxide has become a promising material for silicon microelectronics because at least of three reasons: i) with its high dielectric constant (20–26), CeO2 is considered as a candidate for replacing SiO2 in silicon devices, for example, as a storage capacitor in dynamic random access memory devices; ii) excellent lattice match with silicon, which means a very good epitaxy on silicon; iii) good chemical stability, iiii) inexpensiveness [2,3,4]
Thin (80 nm) cerium oxide films in Al/ncCeOx/Si/Al structures were obtained by the vacuum flash evaporation method from CeO2 powder [8]
The present work shows that application of inexpensive flash evaporation method of CeOx films deposition at relatively low temperatures (200 – 300 0C vs 1100 – 1300 0C needed for SiO2 growth) simplifies the technology of producing of CeOx films, and enables fabrication of semiconductor/dielectric interfaces of enhanced quality

Summary

Introduction

Cerium oxide has become a promising material for silicon microelectronics because at least of three reasons: i) with its high dielectric constant (20–26), CeO2 is considered as a candidate for replacing SiO2 in silicon devices, for example, as a storage capacitor in dynamic random access memory devices; ii) excellent lattice match with silicon, which means a very good epitaxy on silicon; iii) good chemical stability, iiii) inexpensiveness [2,3,4]. The cerium oxides have properties that match or exceed those of all the other materials listed and yet have been studied far less than all the others in terms of their use as a gate dielectric. It is clear that CeO2 has properties equal or superior to those of the other materials shown above in terms of qualities for forming a silicon heterostructure [6]

Objectives

Discussion

Conclusion