Achieving a low interfacial density of states in atomic layer deposited Al2O3 on In0.53Ga0.47As

Abstract

Atomic-layer-deposited Al2O3 on In0.53Ga0.47As with short air exposure between the oxide and semiconductor deposition has enabled the demonstration of nearly ideal frequency-dependent and quasistatic capacitance-voltage (C-V) characteristics. The excellent quasistatic C-V characteristics indicate a high efficiency of 63% for the Fermi-level movement near the midgap. A low mean interfacial density of states (D¯it)∼2.5×1011 cm−2 eV−1 was determined under 1 MHz using a charge pumping method, which was also employed to probe the depth profile of bulk traps (Nbt) and the energy dependence of Dit at 50 kHz: a low Nbt∼7×1018 cm−3 and a Dit of (2–4)×1011 cm−2 eV−1 in the lower half of the band gap and a higher Dit of ∼1012 cm−2 eV−1 in the upper half of the band gap. The employment of charge pumping method has given a more accurate determination of Dit, which is usually overestimated using other commonly methods such as the Terman, conductance, and high-low frequencies due to the influence of weak inversion at room temperature.

Effect of postdeposition anneals on the Fermi level response of HfO2/In0.53Ga0.47As gate stacks

“…The CV behavior of the nitrogen annealed stack, with its large stretch-out and significant frequency dispersion at negative biases, is very similar to what has been reported for many high-k oxides on In 0.53 Ga 0.47 As at room temperature in the literature. 2,3,9, [14][15][16][17][18] For a more quantitative analysis, Fig. 2 shows a comparison of ideal and experimental 1 MHz CV curves for all three stacks shown in Fig.…”

Comparison of methods to quantify interface trap densities at dielectric/III-V semiconductor interfaces

“…There are two possible explanations for these features. The first, suggested frequently in the literature, 10,11,13,16,44 explains the upturn of capacitance at negative bias with minority carrier ͑true or weak inversion͒ response. Minority carriers are expected at higher frequencies for In 0.53 Ga 0.…”

“…The discrepancies in the D it values extracted from the same device using different methods can exceed half an order of magnitude. [8][9][10]13 There is substantial variation in the reported D it even when similar sample preparation and D it extraction methods were used. 9,13 The goal of this paper is to compare the most commonly used methods, identify potential pitfalls and develop reliable and robust guidelines for the quantification of D it of high-k/III-V interfaces.…”

“…7 As summarized in Table I for high-k / In 0.53 Ga 0. 47 As interfaces, many different methods have been employed, such as interpretation of shifts in the capacitance-voltage ͑CV͒ curves with gate metal work function, 11,23 the combined high-low frequency capacitance ͑Castagné-Vapaille͒ method, 14 the Terman ͑high-frequency capacitance͒ method, 16,19,20 the Berglund integral, 11,12,27 the conductance method, 8,10,13,[15][16][17][18]21,24,28 and the Fermi level efficiency method. 29 As can be seen from Table I, reported D it values differ by several orders of magnitude, ranging from low-10 11 cm −2 eV −1 to exceeding 10 13 cm −2 eV −1 .…”

MBE—Enabling technology beyond Si CMOS

“…Residual In 2 O 3 and Ga 2 O 3 , and their hydro-oxides at the ALD-oxide/InGaAs interface were further reduced with air exposure o10 min from the MBE system to an ex-situ ALD reactor, resulting in a CET of 1.0 nm with HfO 2 [26] and a D it in the range of 10 11 eV À 1 cm À 2 with Al 2 O 3 [27]. In contrast, there are no such native oxides at the interfaces using MBE-GGO [28].…”