Download or read book Atomistic Modeling of Aluminum Nitride/gallium Nitride HEMTs for Applications in Harsh Environments written by Dylan B. John and published by . This book was released on 2011 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: AlN/GaN high-electron mobility transistors (HEMT) are subject to internal structural and electrostatic fields originating mainly from: (i) the fundamental crystal atomicity and the interface discontinuity between dissimilar materials, (ii) atomistic strain, (iii) piezoelectricity, and (iv) spontaneous polarization (pyroelectricity). Through numerical simulations, this study explores the origin and effects of these competing internal fields on the electrostatics and the I-V characteristic of scaled nitride HEMT structures. It is shown that strain in these devices is asymmetric and long-ranged (demanding simulations using millions of atoms). The resulting piezoelectric polarization is large and atomistic in nature. This finding has been validated using available experimental data. The polarization fields alone can induce channel carriers at zero external bias and lead to a significant increase in the ON current.