M.Sc. Semina on thin film deposition technique(CBD)

1. FEDERAL UNIVERSITY OF KASHERE
SCHOOL OF POSTGRADUATE
DEPARTMENT OF PHYSICS
SEMINAR PRESENTATION
(PHY 8207)
ON
THIN FILMS AND CHEMICAL BATH DEPOSITION
TECHNIQUE
BY
SALIHU, MUHAMMAD ALIYU
SPS/20/PHY/MSC/0003
SUPERVISOR
dR. q. a. adeniji
FEBRUARY, 2023

2. Contents
 Thin Films
o Introduction and overview
o Properties
o Types and
o Applications
 Thin Film Deposition techniques
 Chemical Bath Deposition Technique(CBD)
o Principle of CBD
o Factors affecting CBD
 Thin films Characterization
 Advantages of CBD
 Conclusion

3. Introduction and overview
 The layer of material having the
thickness of the order of 1 micron
(10,000 A0,1000 nm) kept over a
substrate is described as Thin Film.
 Bulk material have fixed properties like
electrical resistivity, electric
conductivity and optical
opacity(Muhtade et al., 2017)

4. Introduction and overview

5. Introduction and overview
Thin = less than about 1 micron(10,000 A0, 1000 nm).
Film = layer of material on a substrate.
Research on thin films leads breakthrough in the field of electronics,
optics, space science, aircrafts, defense and other industries.
 When the thickness is
reduced, beyond certain
limits these materials
shows a drastic change in
properties. This is called
size effect(Olayinka et al.,
2019).

6. Properties of Thin Films
 Different from bulk materials.
 Thin film may be:
• not fully dense
• Under stress
• Quasi-2D (very thin films)
• Different defect structure from bulk
• Strongly influenced by surface and interface
effect(change electrical, magnetic, optical, thermal
and mechanical property)
• (Samira, 2021)

7. Types of Thin Film Structure
Kodigala (Phone)

8. Applications
 microelectronics – VLSI, ULSI, and GSI
 magnetic sensors – sense I, B or change in them
 gas sensors
 flexible solar cell
 optics – anti-reflection coatings
 Wear resistance
 Etc…. (Seshan 2002)

9. Thin Film Preparation Methods
(Ezeama et al., 2002)l

10. Basic Principle of Chemical Bath Deposition
Technique(CBD)
Thin film stages occurs in three Steps:
Creation of Atomic/Molecular/Ionic species
Transport of these species through a medium and
Condensation of the species

11. Basic Principle con’t
 Make Precursor solutions
 Add them with some complexing agents by stirring in beaker
 Adjust pH by adding a pH adjuster solution like ammonia (NH3),
NaOH etc.
 Insert substrate into the beaker vertically
 Keep this beaker into constant temperature bath for some time interval
at constant temperature
 Optimize all the parameters like pH, bath temperature, molar
concentration, bath time by keeping some constants and also by trail
and error method to obtain good and quality film on the
substrate(Mahanty et al., 1999).

12. Experimental Setup

13. Factors Affecting the CBD Deposition
 Effect of complexing agent(decreases metal ionic conc. leading to a
larger terminal thickness)
 Effect of CBD pH(increases the deposition rate)
 Effect of bath temperature(increase dissociation of the complexing
agent)
 Effect of Deposition time(incresses the structural, morphological
and optical properties)
 Effect of concentration of cation and anion sources(nature of the
reactance influences the whole physical and chemical properties of
the film)
 Effect of type of precursor sources (influences the composition of
the product, deposition rate and terminal thickness )
 Ageing of the stock solution (affect the reproducibility and quality
of the deposition film)

14. Characterization
 Surface morphology and elemental properties (SEM and EDS)
 The structural and optical properties (XRD and UV-
vis/photoconductivity )
 The electrical properties (4 point probes)
 The grain size (scanning electron microscopy) and the accurate
thickness of the film (profilometer/the atomic force microscopy)
 The optical characterization/properties (e.g the band gap,
transmittance, reflectance and absorbance) via UV-VIS
spectrometer.
 The morphological characterization (Scanning electron
microscope).
 The structural characterization (XRD).
 The semiconductor type (Hall Effect machine)

15. Advantages of CBD
Low cost of production
Deposition is possible in UG lab
Low temperature processing
Easy to handle
Safe procedure with less environmental hazard
Reproducibility is very high
Wastage can be minimize
Large area deposition is possible

16. conclusion
CBD yield the following :
Stable
Adherent
Uniform and
Hard film with good reproducibility by a
simple process

17. Thank you for listening