Effects of hydrogen on positive charges in gate oxides

Abstract

Articles you may be interested inCharge trapping in alumina and its impact on the operation of metal-alumina-nitride-oxide-silicon memories: Experiments and simulations Charge injection from gate electrode by simultaneous stress of optical and electrical biases in HfInZnO amorphous oxide thin film transistor Appl. Phys. Lett. 97, 193504 (2010); 10.1063/1.3508955Hot-carrier-induced oxide charge trapping and interface trap creation in metal-oxide-semiconductor devices studied by hydrogen/deuterium isotope effect Positive charge formation in gate oxides is a main source for the instability of the state-of-the-art metal-oxide-semiconductor device. Despite past efforts, the relation between hydrogenous species and positive charges is not fully understood. In this work, the effects of hydrogen on positive charges will be investigated at both elevated temperature ͑e.g., 400°C͒ and room temperature. At 400°C, it is found that hydrogen can convert some defects into hole traps. Three different types of positive charges have been reported recently. They are as-grown hole traps, anti-neutralization positive charges ͑ANPC͒, and cyclic positive charges ͑CPC͒. Although an exposure to hydrogen at 400°C neutralizes all three, impacts of hydrogen on these three types of defects are markedly different. After the hydrogen-induced neutralization, the defect responsible for ANPC is fully recovered and is the same as that in a fresh device. In contrast, the defect for CPC is not fully recovered and can be reactivated easily by stresses. The as-grown hole trap can be converted to ANPC through hydrogenation. At room temperature, it will be shown that there are two parallel processes for forming positive charges. One involves hydrogen and the other is through hole trapping. The relative importance of these two depends on the relative density of hydrogen against that of holes.

The as-grown-generation (AG) model: A reliable model for reliability prediction under real use conditions

“…Generating new traps is an independent process from filling AHTs [27][28][29][30]. The AHTs are located below Si Ev, while the generated hole traps are above Ev [13,31,32].…”

A Discharge-Based Pulse Technique for Probing the Energy Distribution of Positive Charges in Gate Dielectric

“…Its impact can be assessed by comparing the energy distribution extracted from different discharge time. The ∆Vt obtained from discharge time of 10s, 50s and 100s under each Vdischarge in Fig.8 is converted to effective charge density [21,22], i.e. ΔNox=|ΔVt|× Cox/q, and plotted against Vdischarge in Fig.…”

NBTI prediction and its induced time dependent variation

“…The positive charges in gate dielectric can be divided into two groups: as-grown hole traps (AHTs) and generated defects (GDs) [6][7][8][9][10][11][12][13][14][15][16][17][18]. AHTs are located below Si valence band edge, Ev, while GDs are above Ev [6,7], as shown in Fig.…”

“…Once all AHTs are filled, they saturates, but the GDs follow the power law without saturation [2,3]. Filling AHTs and generating GDs are two independent processes [10][11][12][13][14]. This understanding has led to the As-grown-Generation (AG) model,…”

“…(1) [2]. To achieve reliable prediction in this case, an As-grown-Generation (AG) model has been proposed, based on the framework for positive charges in gate dielectric [6][7][8][9][10][11][12][13][14][15][16][17][18].…”