Surface Passivation of Crystalline and Polycrystalline Silicon Using Hydrogenated Amorphous Silicon Oxide Film

Abstract

Excellent passivation properties of hydrogenated amorphous silicon oxide (a-SiOx:H) prepared by very high frequency plasma-enhanced chemical vapor deposition (VHF PECVD) at a low substrate temperature (170 °C) on crystalline and polycrystalline silicon (Si) wafers are reported. Films were characterized by ellipsometry, Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible (UV–vis) spectrophotometry, and dark-conductivity and photoconductivity measurements. A comparison of the results with those for different passivation layers such as hydrogenated amorphous silicon carbon nitride (a-SiCxNy:H), hydrogenated amorphous silicon nitride (a-SiNx:H), and hydrogenated amorphous silicon (a-Si:H) reveals their superiority as an excellent passivation layer for p-type crystalline Si as well as polycrystalline Si. A maximum effective lifetime of 400 µs was measured for 1–10 Ω cm, 380-µm-thick p-type c-Si using a micro-photocurrent decay (µ-PCD) system. Fixed charge density (Qf) was estimated by high-frequency (1 MHz) capacitance–voltage measurement using a metal–insulator–silicon structure (CV-MIS). The effect of annealing temperature on surface passivation in a nitrogen atmosphere was also studied.

Improvement of amorphous silicon n-i-p solar cells by incorporating double-layer hydrogenated nanocrystalline silicon structure

“…5 shows the variation of C −2 with V for the solar cells with and without a p-nc-Si:H buffer layer deduced from the C-V measurements at 1 MHz. The frequency of 1 MHz is the same as that adopted by several workers to investigate the hydrogenated amorphous silicon materials using the C-V characteristics [19][20][21]. In Fig.…”

Influence of Chemical Composition and Structure in Silicon Dielectric Materials on Passivation of Thin Crystalline Silicon on Glass

“…Such a scenario is also probable since several studies have demonstrated that, in addition to field effect passivation, silicon dielectric layers with relatively high hydrogen content chemically passivate silicon via hydrogen release during a subsequent heating step. 31,44 Comparing the chemical bond densities in Tables 6 and 8 with the V oc and J sc values in Tables 7 and 9, respectively, gives a global relationship between the chemical bonding of the passivating layer and the performance of the test cells. Without HPP, increasing [Si−H] in the passivating layer increased both J sc and V oc , in agreement with reports for multicrystalline silicon.…”

Heat treatment in 110 °C liquid water used for passivating silicon surfaces

“…The passivation of semiconductor surfaces is important to achieve a long lifetime of photo-induced minority carriers, which is required for fabricating high-performance photosensors and photovoltaic devices [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Many famous passivation techniques have been developed for surface passivation, for example, formation of thermally grown SiO 2 layers [20], hydrogenation treatment [21,22], fieldeffect passivation caused by fixed charges in SiN or aluminum oxide [23,24], and high-pressure H 2 O vapor heat treatment [25][26][27][28][29].…”