P-N Junction Doping Profile Extraction via Inverse Modelling

In accordance with the requirements for the degree of Bachelor of Engineering (Honours) in the division of Electrical Engineering, I hereby submit for your consideration this thesis entitled " P-N junction doping profile extraction via inverse modelling ". The work was performed under the supervision of Associate Professor Y.T Yeow. I declare that the work submitted in this thesis is my own, except as acknowledged in the text and footnotes. This work has not been previously submitted for a degree at the University of Queensland or at any other institution. Yours sincerely, ____________ Tong Lee Too iii Acknowledgement I would like to thank my supervisor, A. Prof Y.T. Yeow for his precious guidance, time and advice for this project. Following that, I would like to thank Ron Rasch from Centre for Microscopy and Microanalysis for helping me take photograph of the wafers under test using the electron microscope. Next, I would like to thank Peter Allen who has been professional and helpful in assisting me in setting up equipment required in this thesis. Finally, I would like to thank my friends and family for their support and encouragement throughout my undergraduate study at the University of Queensland. In particular, I would like to thank Tan Yancun for helping me prove read this thesis. Abstract With the increase complexity of device fabrication process and downsizing of semiconductor devices, there is an increasing importance to measure the doping profile of the final device [1]. Knowledge of doping profiles of semiconductors devices allows the determination of electrical characteristics of the devices. Extracted doping profiles can also act as an indicator of the fabrication process of the devices. Over the years, many methods have been developed by researchers to extract doping profiles of semiconductor devices. The conventional analysis of capacitance-voltage (C-V) measurement is widely used for doping profile extraction due to its simplicity. However, this analysis provides only an approximate value of the actual doping profile of the device [2]. It could only extract doping profile of the less highly doped side of P-N junctions and the extracted profile is limited. In this thesis, a more accurate method of doping profile extraction for P-N junction is presented. The conventional method is extended via an inverse modelling approach in hope to overcome existing limitations. The inverse modelling process is done in device simulator ATLAS. An initial estimate of the doping profile is treated as input …