p~+–n~-–n~+-type power diode with crystallineanocrystalline Si mosaic electrodes

摘要

Using p~+-type crystalline Si with n~+-type nanocrystalline Si (nc-Si) and n~+-type crystalline Si with p~+- type nc-Si mosaic structures as electrodes, a type of power diode was prepared with epitaxial technique and plasmaenhanced chemical vapor deposition (PECVD) method. Firstly, the basic p~+–n~-–n~+-type Si diode was fabricated by epitaxially growing p~+- and n~+-type layers on two sides of a lightly doped n~--type Si wafer respectively. Secondly, heavily phosphorus-doped Si film was deposited with PECVD on the lithography mask etched p~+-type Si side of the basic device to form a component with mosaic anode. Thirdly, heavily boron-doped Si film was deposited on the etched n~+-type Si side of the second device to form a diode with mosaic anode and mosaic cathode. The images of high resolution transmission electronic microscope and patterns of X-ray diffraction reveal nanocrystallization in the phosphorus- and boron-deposited films. Electrical measurements such as capacitance–voltage relation, current–voltage feature and reverse recovery waveform were carried out to clarify the performance of prepared devices. The important roles of (n~-/Si/(p~+c-Si and (n~-/Si/(n~+c-Si junctions in the static and dynamic conduction processes in operating diodes were investigated. The performance of mosaic devices was compared to that of a basic one.