Detection of Thermal Transport Using GIDL (Gate Induced Drain Leakage) Current

Abstract

We report a method and experiment to detect the transport of the lattice phonons generated by hot electrons during the MOSFET operation. We used the band-to-band tunneling (BTBT) device as a phonon sensor. This method is useful to detect the phonon energy even in non-equilibrium as well as the equilibrium. We explain the fundamental principle that the BTBT current can estimate the phonon energy even in non-equilibrium. In order to validate the idea, we measured the phonon energy generated by the hot electron scattering at a nearby MOSFET (as a phonon generator) with the gate-induced drain leakage (GIDL) current of the MOSFET (as a phonon sensor). For the experiment, we designed the 5-transistors scheme, in which one transistor is the phonon sensor and the other 4 transistors are the phonon generators. In this experiment, we use the lock-in technique in order to measure the increment of the GIDL current which is caused by an arrival of the phonons transported from the phonon generator. In the experiment at the room temperature, during the operation of each phonon generator on different distances and the gate bias conditions, we estimate the equivalent lattice temperature from the variation of the GIDL current on the assumption of the system in the near-equilibrium. Moreover, by performing the same experiment at low temperature, we measure the phonon energy under a non-equilibrium with the phonon sensor based on the BTBT. Additionally, our phonon sensor has the advantage of high spatial resolution, since the GIDL current results from the BTBT in a very small overlap region (about 10 nm) of the gate and drain of the MOSFET. With this advantage, we observed the retardation of the phonons generated in a MOSFET, by applying small signal modelling to the method. Finally, as the measurements were made at different temperatures, we observed the change in the phonon transport properties due to changes in thermal conductivity.