Measurement of work function of transition metal nitride and carbide thin films

Abstract

Articles you may be interested inGeneric trend of work functions in transition-metal carbides and nitrides Influence of the negative oxygen ions on the structure evolution of transition metal oxide thin films A systematic density functional theory study of the electronic structure of bulk and (001) surface of transitionmetals carbides Application of compact microwave ion source to low temperature growth of transition metal nitride thin films for vacuum microelectronics devices Rev.Work functions of transition metal nitride and carbide thin films were measured. The materials investigated were ZrN, NbN, HfN, TaN, HfC, and TaC. The films were prepared either by radio-frequency magnetron sputter deposition or by ion beam assisted deposition. The work function was measured by Kelvin probe in air. The work functions of ZrN and HfN ranged between 4.6 and 4.7 eV, and were similar to or slightly lower than that of NbN and TaN, 4.7 or 4.8 eV. The work function of TaC was approximately 5.0 eV. The higher work function of carbide may be attributed to lower electronegativity of carbon as compared to nitrogen.

Magnetoresistance, Gating and Proximity Effects in Ultrathin NbN-Bi2Se3 Bilayers

“…We note that generally a depletion layer forms at the interface of a metal electrode in contact with a semiconductor provided φ m > φ s where φ m and φ s are the work functions of the metal and the semiconductor, respectively [21]. Here however, the opposite case occurs and an accumulation layer forms since φ m < φ s where the metallic NbN layer has φ m = 4.7 V [22] and the "semiconductor" Bi 2 Se 3 layer φ s = 5.6 V [23]. The gate basically adds or removes charges from this accumulation layer.…”

Electrical and Thermal Stability of ALD-Deposited TiN Transition Metal Nitride Schottky Gates for AlGaN/GaN HEMTs

“…The increased reverse leakage may be due to the lower TiN barrier height with the AlGaN (0.5 eV for TiN versus 0.7 eV for Ni, as calculated from temperaturedependent gate I-V measurements), or to the formation of a leaky interfacial layer in the initial stages of TiN deposition. 6,7,[17][18][19] The 2DEG density (n s ) and carrier mobility (μ 2DEG ) were found to be degraded more (relative to the as-grown structure) in the reference sample than in the sample subjected to the TiN ALD growth process. The degradation was largely attributed to fluorination of the AlGaN barrier under the gate during the SiN x recess etch process.…”

“…9 No residual precursor/carbon contamination was detectable via X-ray photoelectron spectroscopy (XPS). Ti/Au top gate contacts were then fabricated by E-beam deposition and liftoff, and were used as an etch mask for self-aligned SF 6 -RIE etching to remove the TiN outside the gate regions. Calibration witness samples were again utilized to minimize over-etching the TiN into the underlying SiN x layer.…”

“…• C. [5][6][7][8] TiN can also be deposited by versatile methods such as atomic layer deposition (ALD), reactive sputtering, and molecular beam epitaxy (MBE) that can be easily integrated into conventional HEMT process flows. 7,9,10 Despite this promise, limited work has been done to assess the effects of a TiN gate on HEMT reliability under extended electrical or thermal stress, and previous studies have exclusively focused on sputtered TiN rather than ALD TiN.…”

Deposition of Niobium Nitride Thin Films from Tert‐Butylamido‐Tris‐(Diethylamido)‐Niobium by a Modified Industrial MOCVD Reactor

“…Several materials have been investigated as alternative gate electrodes, including TaN and NbN. [48][49][50] In order to replace polysilicon in CMOS transistors, a new metal gate electrode material should be highly conductive and show the correct work function for both nFET and pFET devices. For pFET a work function of 5.15 eV needs to be achieved in order to meet the requirements as a gate electrode.…”