Title :
Physics of electron transport in nitride-based material
Author_Institution :
Dept. of Electr., Comput., & Syst. Eng., Rensselaer Polytech. Inst., Troy, NY, USA
Abstract :
In AlN/InN/GaN-based semiconductors, the polar optical phonon energy is large (much larger than the thermal energy at room temperature). As a consequence, the dominant optical polar scattering occurs in two steps: photon absorption and re-emission (resulting in an effectively elastic scattering process). In high electric fields, an electron runaway plays a key role in determining the peak field and peak velocity in these compounds. The runaway effects are further enhanced in the two dimensional electron gas at the AlGaN/GaN or AlGaInN-InGaN heterointerfaces. As a result of the runaway and quantization effects, the peak electron drift velocity and peak electric field of the 2D electrons in compound semiconductors are smaller than for the 3D electrons in these materials. In very short (e.g. sub-0.1 micron) GaN-based structures, ballistic and overshoot effects become important. In a deep submicron structures, the ballistic effects in low electric fields reduce an apparent value of the low field mobility because of a finite electron acceleration time in the structure. In long channel devices, the electron mobility in AlGaN/GaN or AIGalnN/InGaN heterostructures at cryogenic temperatures is limited by acoustic scattering, electron transfer from 2D to 3D states, and by the alloy scattering. Relatively high values of the electron mobility and very high values of the 2D electron gas densities in nitride heterostructures also make them attractive candidates for plasma wave electronics devices operating in the terahertz range of frequencies.
Keywords :
III-V semiconductors; aluminium compounds; ballistic transport; cryogenics; electron density; electron mobility; gallium compounds; high field effects; indium compounds; light absorption; light scattering; phonons; semiconductor heterojunctions; two-dimensional electron gas; wide band gap semiconductors; 2D electron gas densities; 3D electrons; AlGaN-GaN; AlN-InN-GaN; GaN-based structures; acoustic scattering; alloy scattering; ballistic effects; compound semiconductors; cryogenic temperatures; deep submicron structures; elastic scattering process; electron drift velocity; electron mobility; electron runaway; electron transfer; electron transport; finite electron acceleration time; heterointerfaces; high electric fields; long channel devices; low field mobility; nitride heterostructures; nitride-based material; optical polar scattering; overshoot effects; photon absorption; plasma wave electronics devices; polar optical phonon energy; quantization effects; reemission; terahertz range of frequencies; two dimensional electron gas; Acoustic scattering; Aluminum gallium nitride; Electron mobility; Electron optics; Gallium nitride; Optical scattering; Particle scattering; Physics; Plasma temperature; Semiconductor materials;
Conference_Titel :
Optoelectronic and Microelectronic Materials and Devices, 2002 Conference on
Print_ISBN :
0-7803-7571-8
DOI :
10.1109/COMMAD.2002.1237177