Overview

The energy distribution of electrons transported through intrinsic AlN was directly measured as a function of applied field and AlN film thickness. The electron energy distribution featured kinetic energies higher than that of completely thermalized electrons. Transport through films thicker than 95 nm at an applied field between 200 kV/cm and 350 kV/cm occurred as steady-state hot electron transport following a Maxwell ian energy distribution with a characteristic carrier temperature. At higher fields (470 kV/cm), intervalley scattering was evidenced by a multi-component energy distribution featuring a second peak at the energy position of the first satellite valley. Velocity overshoot was observed in films thinner than 95 nm and at fields greater than 510 kV/cm. In this case, a symmetric energy distribution centered at an energy above the conduction band minimum was measured, indicating that the drift component of the electron velocity was on the order of the thermal component. A transient transport length of less than 80 nm was deduced from these observations.

Keywords: High field transport; AlN; runaway.

1. Introduction

Experimental characterization of the electronic properties of aluminum nitride (AlN) is scarce and most of the current understanding originates from theoretical estimates. Besides the basic electronic properties (e.g., Hall mobility and carrier concentration), not much more is known about the nature of electron transport in AlN and transient effects have not been studied experimentally at...