NH₃ Plasma Interface Modification for Silicon Surface Passivation at Very Low Temperature

Abstract

The effect of passivation layers (SiOX, SiNX, etc.) using plasma-enhanced chemical vapor deposition (PECVD) for crystalline silicon solar cells showed high surface recombination with decreasing of deposition temperature (<300 °C). The surface of Czochralski (Cz) monocrystalline silicon (c-Si) wafer was exposed to an NH3 plasma before the low-temperature deposition of silicon nitride (SiNX) layer or amorphous silicon (a-Si:H) layer in a system respectively. The effect of NH3 plasma treatment for the interface was observed by microwave photoconductance decay (µ-PCD), quasi-steady-state photoconductance (QSSPC), Fourier transform infrared spectroscopy (FT-IR), secondary ion-microprobe mass spectrometry (SIMS), and X-ray photoemission spectroscopy (XPS). The effective lifetime (τeff) with NH3 plasma treatment exceeded τeff without the treatment. Even in the case of very low deposition temperature (100 °C), τeff is improved dramatically (about 38 times). This NH3 plasma treatment effect was caused by hydrogenation and carbon cleaning from the SIMS measurement. It was found that SiNX films with excellent surface passivation properties can be deposited at 100 °C.

Minority Carrier Annihilation in Lateral Direction Caused by Recombination Defects at Cut Edges and Bear Surfaces of Crystalline Silicon

“…Excellent techniques and models for analyzing minority carrier lifetime and carrier recombination defect states have been reported. [4][5][6][7][8][9][10][11][12] We have also developed techniques for measuring the density of minority carriers and the minority carrier effective lifetime eff using a 9.35 GHz microwave transmittance measurement system with continues wave (CW) as well as periodic pulsed light illumination. [13][14][15] We have established the relationship of the density of minority carriers with eff in cases of CW and periodic pulsed light illumination.…”

Investigation of Silicon Surface Passivation by Microwave Annealing Using Multiple-Wavelength Light-Induced Carrier Lifetime Measurement

“…The long minority carrier effective lifetime eff of semiconductors is important for solar cells and photosensors. [1][2][3][4][5][6][7][8][9][10][11] A long eff allows the minority carriers to well diffuse in the whole region of a semiconductor substrate with a low annihilation rate. It therefore results in a high short-circuit current-and a high open circuit voltage for semiconductor solar cells.…”

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].…”