Gate-Leakage and Carrier-Transport Mechanisms for Plasma-PH₃ Passivated InGaAs N-Channel Metal–Oxide–Semiconductor Field-Effect Transistors

Abstract

Gate leakage mechanism of the HfAlO plasma-PH3 passivated and non-passivated In0.53Ga0.47As N-channel metal–oxide–semiconductor field-effect transistors (N-MOSFETs) have been evaluated, in order to correlate the quality of the oxide deposited with the gate leakage mechanisms observed. At temperatures higher than 300 K, trap-free space charge limited conduction (SCLC) mechanism dominates the gate leakage of passivated device but non-passivated device consists of exponentially distributed SCLC mechanism at low electric field and Frenkel–Poole emission at high electric field. This Frenkel–Poole emission is associated with energy trap levels of ∼0.95 to 1.3 eV and is responsible for the increased gate leakage of non-passivated device. In addition, the electrical properties of the non-passivated device has also been extracted from the SCLC mechanism, with the average trap concentration of the shallow traps given as 1.3×1019 cm-3 and the average activation energy given as ∼0.22 to 0.27 eV. The existence of these defect levels in non-passivated device can be attributed to the interdiffusion of Ga/As/O elements across the HfAlO/In0.53Ga0.47As interface. On the other hand, passivated device does not contain Frenkel–Poole emission nor exponentially distributed SCLC mechanism, indicating a reduction in traps in the bulk of the oxide. In addition, the temperature dependent characteristics of off-state leakage have also been evaluated to provide insight into the off-state mechanism. The off-state leakage of both passivated and non-passivated device is determined by junction leakage, with Shockley–Read–Hall mechanism being its main contributor, and has activation energy of 0.38 eV for passivated device and 0.4 eV for non-passivated device. From I d∝T -0.37 observed for passivated device, in comparison to I d∝T -0.18 for non-passivated device, we have further confirmed the phonon scattering dominance of the passivated device at high electric field.

Interfacial X‐ray photospectrometry study of In 0.53 Ga 0.47 As under different passivation treatments for metal oxide semiconductor field effect transistor devices

“…Elimination of the surface charges by passivation techniques has already been used to reduce the effect of the D it . Several passivation methods such as wet solution [2], plasma [3] and UV‐ozone [4] have been proposed as the solution for this problem.…”