Solar Cell Metallization Lab Module

1
Solar Cell Metallization Lab Module

• Final Presentation for
• Senior Design Project
• Luis Curiel
• Dr. Emily Allen, Advisor
• May 10, 2002

2
Final Report Outline

• Introduction
• Background
• Solar cell process flow
• Work accomplished
• Conclusion
• Future work

3
Introduction

• Demand for electrical power is ever increasing
• conservation
• alternative energy sources
• Solar energy
• renewable energy source
• solar cell
• Solar cell
• involves semiconductor technologies
• not necessarily environmentally green

4
Background
E
p-type Si
n-type Si
conduction band
-

e-
valence band


e-
photons
e- hole pair generation
5
Design Project Goal

• Engr.10 solar cell test lab module
• Spartan solar cell design
• Microelectronics Process Engineering Lab
• Produce a MatE.153 solar cell lab module to
  bridge the solar cell fabrication process with
  the solar cell test lab module

6
Design Project Objectives

• Define student learning objectives
• Design process flow
• Address safety issues
• Produce lab manual
• Create in-lab questions and exit quiz
• Develop a cost spreadsheet

7
Student Learning Objectives

• After completing the lab module, students should
  be able to
• safely operate the photoresist spinner, the mask
  aligner and the wet chem processing equipment
• demonstrate use of MSDS
• describe photolithography
• explain doping of silicon
• use cross sectional sketches to explain solar
  cell operation

8
Design for Safety

• Identify safety hazards, assess risks and design
  safety protocols for the safety hazards
• Safety hazards identified
• chemical exposure
• UV radiation
• Safety protocols
• training
• PPE (personal protective equipment)

9
Wet Chem Safety
D.I. Rinse
Photoresist stripper
Photoresist stripper wet chem bench
10
Solar Cell Process Flow
SiO2
n-type
p-type
Photoresist
Aluminum
n-type
p-type
PR
PR
Al
Al
n-type
p-type
Aluminum
11
Work Accomplished

• Performed experiment
• determined processing time
• 2 MatE.129 students
• eight dummy wafers each
• Participated in running two MatE.153 lab sections
• evaluated safety issues
• confirmed processing time
• 2 groups of 8 students per lab section
• Electrically tested completed solar cell

12
Graph of the Electrical Test Data
Voc
Jsc
13
Student Comments

• Can we test the solar cells to see if they
  work?
• Did we make a solar cell that really works?
• Can I take the solar cell home?
• Are the steps we did to make the solar cell,
  the same steps to make an IC?

14
Student Evaluation

• 21 responses/ 32 students
• 85 recommend that the lab become permanent
• 90 felt testing solar cells would enhance the
  lab
• 23 are not confident in explaining solar cells
• 100 of the students felt safe

15
Results

• Less than 2 hours to complete processing
• Strong interaction with students
• interest
• knowledgeable questions
• hands on
• positive feedback from students
• Safety improvements are needed
• Introduction presentation needs improvement
• Handouts need improvement

16
Conclusion

• Student interest enhanced by hands on activity
• Hands on activity increased interest in testing
  solar cells
• Feasible to safely run 10 lab sections per
  semester

17
Future Work

• Reduce cost of solar cell lab, estimated at
  3,500/semester
• Improve safety training protocols
• Integrate electrical testing of solar cell at the
  end of the lab module

18
Acknowledgments

• Dr. Emily Allen, Department Chair, Chemical and
  Materials Engineering
• Neil Peters, Microelectronics Processing Lab
  Engineer
• Binh Nguyen, Microelectronics Processing Lab
  Assistant