POCl<sub>3</sub> diffusion for industrial Si solar cell emitter formation

doi:10.1007/s11708-016-0433-7

Front. Energy

2017, Vol. 11

Issue (1) : 42-51 https://doi.org/10.1007/s11708-016-0433-7

RESEARCH ARTICLE

POCl₃ diffusion for industrial Si solar cell emitter formation

Hongzhao LI(

), Kyung KIM, Brett HALLAM, Bram HOEX, Stuart WENHAM, Malcolm ABBOTT

School of Photovoltaic and Renewable Energy Engineering, UNSW Australia, Sydney, NSW 2052, Australia

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Abstract

POCl₃ diffusion is currently the de facto standard method for industrial n-type emitter fabrication. In this study, we present the impact of the following processing parameters on emitter formation and electrical performance: deposition gas flow ratio, drive-in temperature and duration, drive-in O₂ flow rate, and thermal oxidation temperature. By showing their influence on the emitter doping profile and recombination activity, we provide an overall strategy for improving industrial POCl₃ tube diffused emitters.

Keywords POCl₃ diffusion emitter recombination oxidation silicon

Corresponding Author(s): Hongzhao LI

Just Accepted Date: 12 October 2016 Online First Date: 08 November 2016 Issue Date: 16 November 2016

Cite this article:

Hongzhao LI,Kyung KIM,Brett HALLAM, et al. POCl₃ diffusion for industrial Si solar cell emitter formation[J]. Front. Energy, 2017, 11(1): 42-51.

URL:

https://academic.hep.com.cn/fie/EN/10.1007/s11708-016-0433-7
https://academic.hep.com.cn/fie/EN/Y2017/V11/I1/42

Fig.1 Illustration of a generic POCl₃ time-temperature/gas flow rate profile for emitter formation including a PSG deposition, drive-in and optional thermal oxidation step

Tab.1 Split values of each key processing parameters during emitter formation

Fig.2 Electrically active phosphorus concentration as a function of depth for various POCl₃:O₂ flow ratio during deposition

Fig.3 Impact of drive-in temperature (left) and duration (right) on doping profiles, ρ _sh and J _0e

Fig.4 Doping profiles (left) and J _0e values (right) as a function of O₂ flow rate during drive-in

Fig.5 IQE as a function of O₂ flow rate during drive-in

Influence of high temperature (930°C, (a)) and low temperature (830°C, (b)) oxidation on doping profiles

IQE of as-diffused and low-temperature oxidized samples

J _0e breakdown of the as-diffused and oxidized samples to illustrate the change in Auger, emitter SRH and surface SRH recombination

Tab.2 EDNA2 modeling parameters to demonstrate the influence of LTO on emitter recombination

Tab.3 Influences of POCl₃ processing parameters on emitter properties

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