Mudassar Meer

Modified angelov model for an exploratory GaN-HEMT technology with short, few-fingered gates

The GaN-based HEMT has emerged as a leading technology option for high-power and high-frequency applications because of its outstanding electronic properties. Angelov-GaN is one of the most popular compact models for GaN-HEMT devices. However, we observed that the standard Angelov-GaN model is unable to accurately model small gate length and gate width HEMT. In this work, we present a modified version of the Angelov-GaN model that captures dc and ac non-idealities in exploratory technology HEMTs. In order to capture these effects we extend the standard DC model using parametric analysis; for RF modeling, we use the open-short de- embedding technique to capture additional pad parasitic effects. The modelled DC I-V and bias dependent S-parameters are found to be in good agreement with measured experimental data.

Observation of quantum oscillation of work function in ultrathin-metal/semiconductor junctions

Quantization in energy level due to confinement is generally observed for semiconductors. This property is used for various quantum devices, and it helps to improve the characteristics of conventional devices. Here, the authors have demonstrated the quantum size effects in ultrathin metal (Ni) layers sandwiched between two large band-gap materials. The metal work function is found to oscillate as a function of its thickness. The thermionic emission current bears the signature of the oscillating work function, which has a linear relationship with barrier heights. This methodology allows direct observation of quantum oscillations in metals at room temperature using a Schottky diode and electrical measurements using source-measure-units. The observed phenomena can provide additional mechanism to tune the barrier height of metal/semiconductor junctions, which are used for various electronic devices.