Semester Break Report

Semester Break Report
Title: Abstract of semester break intern experience, work details and internship output
Assoc. Dr. Mutharasu Devarajan
Intern student: Alexander Lau Buong Siing
12 August 2014
Title: Abstract of semester break intern experience, work details and
internship output
12 August 2014
1. Abstract
Semester break internship began on the 1st
of July right after the semester final exams. A meeting was
set up with Dr. Mutharasu at about 11am. Upon having a brief discussion, I was assigned to Mr. Naveed
to be guided and to learn the ropes in lab 335. I was told to look up on x-ray diffraction (XRD) and thin
films. I had my student matric card programmed to access lab 335 that day too.
The first week was spent on reading about XRD and thin films under Mr. Naveed’s request to get a rough
idea about the two topics. I took the liberty to read briefly about LEDs as well.
The second week (7-11 July) I was told to read up on crystal lattices especially on hexagonal structures.
It was then I discovered the use of Miller Indices and I soon realized how crucial a role it plays on XRD
techniques. I struggled understanding Miller Indices and sought guidance from a fellow senior. As of
now, I have a rough idea about Miller Indices.
During that period until Mr. Naveed’s departure to his hometown for the holidays, he assigned me to
send and retrieve silicon samples from the Crystallography laboratory. Mr. Mustaquim, the gentleman
who operates the XRD machine explained to me briefly how the machine works and that it takes
somewhat 30-40 minutes for a complete analysis.
Throughout the semester break, Ozzy showed Amir and I his chemical vapor deposition (CVD) work and
how the machine operates. Upon Mr. Naveed’s absence, I began lending Ozzy a helping hand with his
CVD work. Mr. Naveed did assign me a task to have 3 of his silicon samples analyzed under the Field
Emission Scanning Electron Microscope (FESEM). As of now, 2 samples have been scanned and the other
required annealing at 100°C then scanned using FESEM. The third one is yet to be scanned because the
FESEM had a faulty component and needed to be repaired. Ozzy and I will see to it that the third silicon
sample is scanned under the FESEM tomorrow (13th
August).
Mr. Naveed also told me to read up on basics of thin film and thin film deposition besides having the
samples scanned under magnification of x100,000.
Besides helping Ozzy and Mr. Naveed, Amir and I also helped Mah to prepare his zinc oxide powder.

12 August 2014
2. Work Details
1. Mr.Naveed
List of topics addressed by Mr. Naveed for me to read up:
a. Thin films
b. Thin film deposition techniques
c. XRD
d. Crystal structures (Primarily hexagonal structures)
e. Miller Indices
f. Linear atomic density of silicon 111 and 110
Errands and other affairs:
a. Send and collect silicon samples from Crystallography lab
b. Rearranged atomic spacing equation for hexagonal structure
c. Did manual calculations relating atomic spacing with Miller index of hexagonal structure
d. Calculated gradient for graphs relating strain in thin films
e. Scanned and annealed silicon samples with Wei Qiang’s and Ozzy’s help.
2. Ozzy
a. Helped set up CVD machine for thin film deposition
b. Helped to clean CVD machine for subsequent thin film depositions
c. Cut aluminium substrates for CVD
d. Polished aluminium substrates for CVD
3. Mah
a. Scrapped zinc oxide powder from alumina balls that were used to grind fine powders of zinc
oxide
b. Cleaned alumina powders using ultrasound apparatus

12 August 2014
3. Internship Output
 Studied the importance of thin film in optoelectronic devices and the physical quantity
of LED efficiency.
 Studied thin film deposition techniques and the thin film deposition technique done by
Ozzy.
 Identified a rough idea on the optimal conditions for Aluminium nitride thin film
deposition
 Studied Bragg’s Law and Miller Index.
 Identify the use of X-Ray Diffraction techniques and studied XRD graphs
 Analyzed factors affecting shape of peaks on XRD graphs and finding solution to reduce
unwanted factors.
 Studied the use of zinc oxide as a dielectric for electronic applications.
Internship Output Details
Thin films are essential for optoelectronic applications. They improve thermal conductivity and also
efficiency for electronic devices such as LEDs. Efficiency of LED is determined by lumens/Watt.
There are many types of thin film deposition techniques; chemical deposition and physical deposition.
Mr. Naveed’s samples are made via sputtering (or spin coating, I’m not sure). Ozzy is trying to identify
ideal parameters for CVD. Right now he has a good idea on the optimal conditions for depositing
Aluminium Nitride thin films and is currently working on Boron Nitride thin films.
d spacing of atomic planes depends on the lattice structure and Miller index. Atomic spacing is
determined by XRD where a graph of “intensity” versus “2θ” is analyzed. The graph obtained will show
peaks are 2θ values depending on the compound that makes the thin film. Shape of the peak is
determined by the stress that is present in the thin film. Annealing can relief some of the stress on the
thin film.
CVD is a very delicate process and different parameters (ie: pressure, flow of nitrogen gas, temperature,
amount of precursor used, orientation of precursor and substrates in the CVD tube) yield different
results which are sometimes unfavorable.
Zinc oxide powder when formed into paste make good dielectric for electronic purposes.

12 August 2014
Incident In The Lab
There was an incident in the lab during the cleaning process of the CVD machine. I was going to dispose
chemical waste (Aluminum chloride) by washing with water. This procedure is usually handled by Ozzy.
Upon contact with water, hydrochloric acid was formed and I felt burning sensation on my left middle
finger. Hydrogen chloride gas was also formed and we had to evacuate the laboratory for a few minutes.
I learnt my lesson. Laboratory safety is indeed important and proper chemical disposal must be adhered
to.
*I also bothered to wear gloves on that day.

12 August 2014
4. Attachments
1. Calculations relating atomic spacing and Miller index done for Mr. Naveed.
1
𝑑2 =
4
3
(
ℎ2+ℎ𝑘+𝑘2
𝑎2 ) +
𝑙2
𝑐2 , Let y=ℎ2
+ ℎ𝑘 + 𝑘2
Finding “c” in terms the written parameters; Finding “a” in terms of the written parameters;
𝑐 = 𝑎𝑑𝑙√
3
3𝑎2−4𝑦𝑑2 →Equation① 𝑎 = 2𝑐𝑑√
𝑦
3(𝑐2−𝑑2 𝑙2)
Assignment 1
Miller index (h,k,l)(002)
CAlInN= XCAlN + (1-X) CInN → Equation②
d=2.70Å, CInN =5.70Å, CAlN =4.98Å, y=0
From Equation①, we find that CAlInN =2d. Since d=2.70Å, CAlInN =5.40Å. Using Equation②, and the
given values for CInN and CAlN , X=
5
12
or 0.417 when rounded off to 3 decimal places.
Assignment 2
Miller index (h,k,l)(103)
CAlInN= XCAlN + (1-X) CInN → Equation②
d= 1.50 Å, CInN =5.70Å, CAlN =4.98Å, y=1
From Equation①, we find that CAlInN =5.16Å. Using Equation②, and the values of CInN and CAlN,
X=0.744 when rounded off to 3 decimal places.

12 August 2014
2. Notes taken regarding topics that Mr. Naveed addressed.
http://en.wikipedia.org/wiki/Thin_film (thin film and deposition techniques)

12 August 2014
Legends:
Activity 1: Reading on topics given by Mr. Naveed
Activity 2: Helping Ozzy with CVD
Activity 3: Zinc Oxide scrapping
Activity 4: Sending and retrieving samples from Crystallography lab
Activity 5: Helping Mr. Naveed with calculations
Activity 6: Polishing aluminium substrates
Activity 7: Sending Mr. Naveed’s samples for FESEM and annealing
Week 1: 1st
-4th
July
Week 2: 7th
-11th
July
Week 3: 14th
-18th
July
Week 4: 21st
-25th
July
Week 5: 28th
-31st
July and 1st
August
Week 6: 4th
-8th
August
Week 7: 11th
-14th
August
Activity 1
Activity 2
Activity 3
Activity 4
Activity 5
Activity 6
Activity 7
Week 1 Week 2 Week 3 Week 4 Week 5 Week 6 Week 7
Gantt Graph of Semester Break
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