PhD Muhammad Usman
CONGRATULATIONS ON YOUR GRADUATION
Mohammad Usman from Islamabad, Pakistan has been a graduate student at school of ICT during the latest years. In february he graduated as a PhD in Electronic and Computer Systems on the topic Impact of ionizing radiation on 4H-SiC devices.
Where are you from and where did you study before coming to school of ICT?
- I am from Pakistan. I have studied at Quaid-i-Azam University, Islamabad before coming to Sweden. I completed my M.Sc. in Physics, and M.Phil in Experimental High Energy Physics from the same university. During my M.Phil I have been part of a CMS-LHC collaboration between Pakistan and the European Center for Nuclear Research (CERN) in Geneva, and I worked at CERN for a short period during my M.Phil research project.
What is your topic and why did you choose it?
- My research topic for PhD was “Impact of ionizing radiation on 4H-SiC devices”. My research coincides with my previous experience in High Energy Physics. However, it is a different field of study with direct implications in radiation environments for High Energy Physics experiments.
Describe your topic in short for a person that doesn't know much about it.
- There are several applications of microelectronics where electronic circuits have to be operated in radiation rich environments. Radiation strongly affect the electronic devices negatively and degrade their operation over the course of time and raise the reliability concerns. Therefore, it is important to improve their reliability for such applications. Silicon carbide (SiC) is one of the materials, which is considered to resist radiation more than conventional semiconductor materials, and the devices made of this material can survive longer in same environment where conventional devices have shorter lifetime. However, the tolerance of SiC devices needs to be studied and should be improved by implementing different techniques. My PhD thesis deals with the reliability of SiC devices in radiation environments, and to improve their performance by using alternate passivation material for these devices.
Tell me something about your results.
- The main results from my thesis can be divided in three major classifications:
- Ionizing radiation degrade the 4H-SiC devices by producing ionization and crystal defects in the device. However, the degradation is less than the devices made of conventional semiconductors.
- With the help of ion implantation in combination with device simulations, the degrading effects in different areas of the devices are understood.
- Aluminum oxide (Al2O3) is a better choice as a dielectric for 4H-SiC from a radiation point of view and can improve the performance of SiC devices.
What would the future bring for your research topic?
- My work will have strong implications on the design and fabrication of SiC based devices specifically planned for the radiation environments.
What are your future plans?
- I completed my PhD on 3rd of February and now I am planning to go back to Pakistan. I will be working in National center for Physics in Quaid-i-Azam University Islamabad. I will start working there as a researcher and my main focus will be on ion beam analysis of materials by using so called Tandem accelerator, which is already installed there.