search query: @instructor Koski, Marko / total: 9
results-list
reference: 1 / 9
« previous | next »
Author:Lindroos, Jeanette
Title:Iron gettering with aluminium and back-surface passivation of chrystalline silicon solar cells
Järngettering med aluminium och bakytspassivering av kristallina kiselsolceller
Publication type:Master's thesis
Publication year:2010
Pages:[13] + 78      Language:   eng
Department/School:Elektroniikan, tietoliikenteen ja automaation tiedekunta
Main subject:Elektronifysiikka   (S-69)
Supervisor:Savin, Hele
Instructor:Yli-Koski, Marko
OEVS:
Electronic archive copy is available via Aalto Thesis Database.
Instructions
close

Reading digital theses in the closed network of the Aalto University Harald Herlin Learning Centre

In the closed network of Learning Centre you can read digital and digitized theses not available in the open network.

The Learning Centre contact details and opening hours: https://learningcentre.aalto.fi/en/harald-herlin-learning-centre/

You can read theses on the Learning Centre customer computers, which are available on all floors.

Logging on to the customer computers

  • Aalto University staff members log on to the customer computer using the Aalto username and password.
  • Other customers log on using a shared username and password.

Opening a thesis

  • On the desktop of the customer computers, you will find an icon titled:

    Aalto Thesis Database

  • Click on the icon to search for and open the thesis you are looking for from Aaltodoc database. You can find the thesis file by clicking the link on the OEV or OEVS field.

Reading the thesis

  • You can either print the thesis or read it on the customer computer screen.
  • You cannot save the thesis file on a flash drive or email it.
  • You cannot copy text or images from the file.
  • You cannot edit the file.

Printing the thesis

  • You can print the thesis for your personal study or research use.
  • Aalto University students and staff members may print black-and-white prints on the PrintingPoint devices when using the computer with personal Aalto username and password. Color printing is possible using the printer u90203-psc3, which is located near the customer service. Color printing is subject to a charge to Aalto University students and staff members.
  • Other customers can use the printer u90203-psc3. All printing is subject to a charge to non-University members.
Location:P1 Ark Aalto  975   | Archive
Keywords:silicon
solar cell
iron
aluminium
segregation
gettering
recombination
passivation
diffusion length
kisel
solcell
järn
aluminium
segregation
gettering
rekombination
passivering
diffusionslängd
Abstract (eng): The purpose of this Master's thesis was to study aluminium gettering of iron impurities in single crystalline silicon.
The intention was to determinate the iron segregation coefficient of aluminium segregation gettering at temperatures lower than 850°C.
Hence, 20 nm of pure aluminium was sputtered onto the backside of 400 µm thick, 2.87 OMEGA -cm p-doped Czochralski silicon wafers, which had been intentionally iron contaminated to a level of (3.36 ± 0.14) x 1013cm-3.
The iron concentration of the silicon wafer was measured through Surface Photovoltage (SPV) diffusion length measurements.
Iron gettering with aluminium at temperatures 800 - 840°C reduced the initial iron concentration to the range 1010 - 1011 cm-3.
Therefore, the iron segregation coefficient ranged from (5.28± 3.38) x 107 at 800°C to (5.23±2.48) x 105 at 840°C.
The resulting high iron segregation coefficient also led to a large iron segregation enthalpy of 21.73 eV at 820 - 840°C.

High temperature annealing of an aluminized crystalline silicon wafer also creates an aluminium back-surface field at the backside of the wafer.
This back-surface field reduces the back-surface recombination and improves the solar cell efficiency together with the iron gettering.
Hence, the back-surface recombination velocity of the aluminium back-surface field was also studied at 800, 850 and 900°C.

In these experiments, 1 and 3.5 µm of pure aluminium was sputtered onto the back surface of clean 200 µm thick, 2.87 OMEGA -cm p-doped crystalline silicon wafers.
The back-surface fields were formed by 30 min anneals and the diffusion lengths of the wafers were measured with Surface Photovoltage.
The measurements resulted in back-surface recom bination velocities of (3.1+1x107-1.85) x 104 cm/s for 3.5 µm aluminium annealed at 850°C and (5.5+3.7-1.6) x 103 cm/s for 3.5 µm aluminium at 900°C.
The 1 µm aluminium layer and the 3.5 µm layer annealed at 800°C did not reduce the back-surface recombination from its initial ohmic value 107 cm/s.
The results confirmed the theoretical assumption that the recombination decreases as a function of increasing aluminium thickness and increasing formation temperature.
ED:2010-03-15
INSSI record number: 39083
+ add basket
« previous | next »
INSSI