FactSheet HELiA - Roth & Rau AG

HELiA
Coating systems for highest efficiency solar cells
The future of solar cells
Heterojunction technology combines advantages of amorphous silicon (thin film) with
advantages of monocrystalline silicon wafers
Highest cell efficiencies of ≥20% with further upside potential
Simple production process with less production steps compared to conventional cell technologies
HELiA - One platform, two coating processes
Key equipment for processing of heterojunction solar cells
Lower production costs due to low temperature processing (compatible with thin wafers)
HELiA PECVD
for intrinsic and doped amorphous silicon deposition
HELiA PVD
for front and back side TCO and metal deposition without flipping the wafers
Roth & Rau AUTOMATiON solutions for loading and unloading
Front Contact
ITO
a-Si:H (p)
a-Si:H (i)
Back Contact
a-Si:H (i)
a-Si:H (n)
ITO
A member of Meyer Burger Group

Texturing
PECVD 1
Back Side i/n
PECVD 2
Front Side i/p
PVD
TCO Front/ Back Side
Back Contact
Screen
Printing
Curing
Cell Tester
& Sorter
Heterojunction Technology process
The Silicon heterojunction technology is an appealing
concept that combines thin amorphous silicon layers with
monocrystalline silicon wafers to realize cell efficiencies
above 20%. The simple structure of the HJT cells needs
less processing steps compared to conventional cell
designs. The excellent surface passivation of the a-Si:H
layer results in high cell efficiency potential.
The superior temperature coefficient of T C
= -0.27%/K
results in a higher energy yield at operating conditions.
Low temperature processing (

Texturing
PECVD 1
Back Side i/n
PECVD 2
Front Side i/p
PVD
TCO Front/ Back Side
Back Contact
Screen
Printing
Curing
Cell Tester
& Sorter
Heterojunction Technology process
Applications
Heterojunction technology applying intrinsic, p- and n-doped a-Si:H layers using PECVD techniques. TCO and
metal layers are sputtered in a PVD process.
Platform
The Roth & Rau HELiA platforms (PECVD and PVD) represent the key devices for processing of heterojunction
solar cells. The PECVD system is capable of depositing uniform, well controlled, thin layers of intrinsic and doped
a-Si:H onto a textured Si-wafer surface. The PVD system provides for front- and backside deposition without
flipping the wafer. Both systems are designed for a throughput of 2400 w/h. The HELiA system platform is based
on a modular design, similar to the well known SiNA ® and MAiA ® systems by Roth & Rau.
HELiA PECVD
- High quality a-Si:H and p/n-Si:H deposition
This system is based on a modular design and,
therefore, it can be configured to the specific customer
needs. The layers are deposited with a PECVD process,
powered by a direct RF-plasma.
The high quality of the amorphous silicon layers enables
the tool also for processing advanced high efficiency
cells such as cells with a heterojunction rear emitter in
combination with a diffused front surface field on n-type
silicon. It can also be used to realize amorphous silicon
backside passivated cells with a diffused emitter on
p-type silicon.
HELiA PVD
- Large area high throughput sputtering at lowest costs
This system has been developed for deposition of TCO
and metal layers by sputter deposition. The tool design
provides for face-up and face-down deposition – front
and back side can be coated without flipping the wafer.
Rotary magnetrons are used for high target utilization,
good uniformity and high throughput at simultaneously
low production costs. Due to its modular concept
various TCO layers, metal layers and layer stacks can
be deposited and make the tool applicable for the
production of different solar cell concepts.
Front Side
Back Side

Texturing
PECVD 1
Back Side i/n
PECVD 2
Front Side i/p
PVD
TCO Front/ Back Side
Back Contact
Screen
Printing
Curing
Cell Tester
& Sorter
Heterojunction Technology process
HELiA PECVD
- Three tool options available
High level tool
Medium level tool
Entry level tool
Cross contamination free solution
Cross contamination may occur
(i-, p-, n-layers)
2,400 w/h throughput (both sides)
optional: 4,800 w/h throughput (both sides)
2,400 w/h throughput
(both sides)
2,400 w/h
throughput
(one side)
Back side processing Front side processing Back side Front side Single side
PM
(i)
PM
PM
(i)
PM
(p)
PM
(i)
PM
(i)
PM
(i)
Cassette Loader
TM
TM
PM
(i)
Handling
(n)
TM TM
TM
Flip
Handling
TM TM TM
(n) (i)
(p)
PM PM PM
Cassette Loader
Cassette Loader
TM
Handling
TM
PM
(n)
Flip
TM
Handling
TM
PM
(p)
Cassette Loader
Cassette Loader
TM
Handling
TM
PM
(p)
Cassette Loader
Option for higher throughput
HELiA PVD
Waferload LM TM Transfer BM
Module (In)
PM
(TCO)
BM
(Out)
TM
BM
(In)
PM
(Metal)
BM
(Out)
TM
Waferload
LM - Load Module
TM - Transfer Module
BM - Buffer Module
PM - Process Module
Data sheet HELiA
Wafer size
6“ wafer
Wafer type
Throughput
n-, or p-type mono
2,400 w/h (optional: 4,800 w/h)
Roth & Rau AG, info@roth-rau.com, www.roth-rau.com