40 YEAR AGO (2)


Actually I am a bit too late to mention that exactly 40 years ago I got my MSc degree from the University of Leuven (Belgium).  As I already indicated in my blog of last year, in 1976 I started to work on my MSc thesis project, and the project finished mid-1977.  The topic of the MSc thesis project was the development of the hardware to drive and read a 256-pixel CCD line sensor.  An object was attached to a small rotating drum and was scanned by means of the CCD line array.  I learned a lot from this practical work, actually not surprising : if you do not know anything of a particular subject, everything you do is new and you constantly learn.

Once I obtained my MSc degree in July 1977, I got the opportunity to stay on-board of the CCD-group and to start a PhD project.  At that time to get funding for their projects, the PhD candidates had to go through a tough oral examination in front of a jury mainly composed out of professors of other (competing) universities.  To prepare myself for this examination, I started working in the CCD-group, headed by prof. Gilbert Declerck. I was involved, in support of another PhD candidate, in the research on the quality of silicon substrates to lower the dark current of the CCDs.  Cor Claeys was my coach during 3 months and he guided me through the clean room.  In this way I got familiar with the silicon processing in general and with the CCD process in particular.  I have seen thousands of silicon defects through the microscope, measured their length and counted the amount of dislocations, stacking faults and other beautiful artifacts.  I got familiar with Wright etch and Secco etch, as well with all kind of annealing steps.  But apparently it was the right preparation for the PhD examination because I could pass the examination, got the funding and could start my own PhD project : the implementation of Indium-Tin-Oxide transparent gate electrodes in the CCD process.  At that time the CCD pixels were based on MOS capacitors with a poly-Si gate electrode.  But the poly-Si did (and still does) absorb part of the incoming light.  To increase the light sensitivity of the pixels, the plan was to replace the poly-Si by a transparent conductive material, such as ITO.  Who could help me with this ?  Actually nobody in our department had any experience with this material and nobody in our department had any experience with the sputtering technique to deposit this material.  Enough challenges ahead for a more-than-interesting CCD-technology project !  The start of a new chapter in my life.


Albert, 13-09-2017.

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