Study on reverse-biased gate leakage current mechanisms in Al2O3/InAlAs metal-oxide-semiconductor structures

Leakage Current Conduction Mechanism of Au-Pt-Ti/ HfO2-Al2O3/n-InAlAs Metal-Oxide-Semiconductor Capacitor under Reverse-Biased Condition

“…It can be verified by linear fitting the curve of ln J versus E i 1/2 with a straight line, where J is the leakage current density and E i is the electric field intensity under reversed bias voltage [25,26]. Schottky emission is temperature dependent, and the slope of linear approximation on the curve of lnJ vs E i 1/2 needs to be consistent at different temperatures, which is the typical feature of Schottky emission [11,25,26]. Therefore, we make the line fit on the measurement curve under different temperatures of 30/50/70 • C in order to identify it correctly by the same scope of the fitting straight line, as shown in Figure 3.…”

“…In this kind of device, InAlAs is most frequently used as the protective layer on the above barrier and as the gate contact semiconductor [1,3], and some reports proposed to deposit a high-k dielectric film on InAlAs, together with the gate electrode, to become a metal-oxide-semiconductor (MOS) capacitor isolated gate structure, in order to effectively suppress the leakage current. HfO 2 that presents a high dielectric constant is a popular candidate as the high-k dielectric [8][9][10], however it does not match well with InAlAs and the poor lattice match would degrade its performance [9]; Al 2 O 3 is used frequently as the high-k dielectric as well [10,11], however its dielectric constant is not high enough, and that will lead to a lower EOT (effective oxide thickness) which is not beneficial for reducing device size. For improvement, the HfO 2 -Al 2 O 3 laminated dielectric layer is proposed, and in this new device structure, a compromised dielectric constant can be achieved and the leakage current can be effectively suppressed [12][13][14].…”

Effect of annealing temperature on interfacial and electrical performance of Au–Pt–Ti/HfAlO/InAlAs metal–oxide–semiconductor capacitor

“…Especially, the leakage current density is significantly low, specifically, it is 1 × 10 −7 A/cm 2 at 3-V bias voltage under annealing temperature of 380 • C, and it is one order of magnitude lower than under annealing temperatures of 280 • C and 480 • C. Furthermore, it is a very low value of leakage current density and is well compared with the values of the existing reports of highk/InAlAs MOS capacitors in Refs. [9,12,15,22].…”

“…[7][8][9] Currently, Al 2 O 3 and HfO 2 are the most commonly used highk materials that are deposited on InAlAs. [10][11][12] In contrast, HfAlO presents a higher dielectric constant than Al 2 O 3, which helps to form higher effective oxide thickness (EOT) under the same physical oxide thickness. Besides, compared with HfO 2 , HfAlO has the low frequency dispersion and high ther-mal stability.…”