Department of Computer Science and Electrical Engineering
The sizes of semiconductor devices have continued to shrink to sub-micron range in the past decade with advances in fabrication technology. When the semiconductor device decrease in size, carriers with high energy are created. These carriers that are known as hot carriers can cause permanent damage to device. Due to this reason hot carrier degradation has become a major concern in the reliability of semiconductor devices
Various measurements had been performed in the past to investigate damages induced by hot carriers. Measurement techniques that had been used include the charge pumping technique and the gate to drain capacitance technique. More recently, the technique of gated-diode measurement (GDM) has been proposed as a better tool to characterise hot carrier induced degradation. This thesis is a report on the experimental work on the evaluation of hot carrier degradation in submicron n-channel MOSFET using the gated diode measurement (GDM).
The device used in this experimental work is an n-channel MOSFET with a channel length of 1.1 um. The experimental work involved measurements of the Id-Vd characteristic, Id-Vg characteristic, reverse biased GDM as well as forward biased GDM. All the measurements were done for before and after electrically stressing of the device. The Id-Vd and Id-Vg measurements indicate the presence of negative charges after stress. However, these measurements can only provide information of the hot carrier effects in the inversion region. The results of the forward biased GDM indicate generation of interface states after hot carrier degradation seen in a significant increase in diode current.
It was concluded that GDM can be used as a sensitive tool for detecting
interface states caused by hot carrier degradation.
Conference Paper:
conference.pdf
Complete Thesis:
Thesis.pdf