Analytical Two-Layer Hall Analysis - Application To Modulation-Doped Field-Effect Transistors

The classical magnetic‐field‐dependent Hall coefficient and conductivity equations are inverted to give the mobilities μ1 and μ2 and carrier concentrations n1 (or p1) and n2 (or p2) in two degenerate bands. The two‐band solution holds for arbitrary magnetic‐field strength as long as quantum effects can be ignored (i.e., kT≳ℏeB/m∗), and it is argued that the analysis can also be applied to two separate layers up to reasonable field strengths. The results are used to determine the two‐dimensional electron gas mobility and carrier concentration in a modulation‐doped field‐effect transistor with a highly doped cap layer

Analytical Two-Layer Hall Analysis - Application To Modulation-Doped Field-Effect Transistors

The classical magnetic‐field‐dependent Hall coefficient and conductivity equations are inverted to give the mobilities μ1 and μ2 and carrier concentrations n1 (or p1) and n2 (or p2) in two degenerate bands. The two‐band solution holds for arbitrary magnetic‐field strength as long as quantum effects can be ignored (i.e., kT≳ℏeB/m∗), and it is argued that the analysis can also be applied to two separate layers up to reasonable field strengths. The results are used to determine the two‐dimensional electron gas mobility and carrier concentration in a modulation‐doped field‐effect transistor with a highly doped cap layer

Charge Storage Effects in Pseudomorphic High Electron Mobility Transistors

We present for the first time results on charging effects in fully fabricated pseudomorphic high electron mobility transistors (PHEMTs), using in-situ, photoemission and conduction (PEC) studies. The experiments were performed on GaAs based FETs with strained InGaAs channels. These studies evaluate hole storage in the channel area which modifies the threshold voltage of the field effect transistors (FETs). Deep level transient spectroscopy (DLTS) measurements were performed and the results compared to the data obtain from the photo studies. Understanding of hole storage is of significance in modeling the devices since holes are attracted towards the channel when the device is pinched off

Charge Storage Effects in Pseudomorphic High Electron Mobility Transistors

We present for the first time results on charging effects in fully fabricated pseudomorphic high electron mobility transistors (PHEMTs), using in-situ, photoemission and conduction (PEC) studies. The experiments were performed on GaAs based FETs with strained InGaAs channels. These studies evaluate hole storage in the channel area which modifies the threshold voltage of the field effect transistors (FETs). Deep level transient spectroscopy (DLTS) measurements were performed and the results compared to the data obtain from the photo studies. Understanding of hole storage is of significance in modeling the devices since holes are attracted towards the channel when the device is pinched off

Benefits of Considering More Than Temperature Acceleration for GaN HEMT Life Testing

The purpose of this work was to investigate the validity of Arrhenius accelerated-life testing when applied to gallium nitride (GaN) high electron mobility transistors (HEMT) lifetime assessments, where the standard assumption is that only critical stressor is temperature, which is derived from operating power, device channel-case, thermal resistance, and baseplate temperature. We found that power or temperature alone could not explain difference in observed degradation, and that accelerated life tests employed by industry can benefit by considering the impact of accelerating factors besides temperature. Specifically, we found that the voltage used to reach a desired power dissipation is important, and also that temperature acceleration alone or voltage alone (without much power dissipation) is insufficient to assess lifetime at operating conditions