Origin and passivation of fixed charge in atomic layer deposited aluminum oxide gate insulators on chemically treated InGaAs substrates

Abstract

We report experimental and theoretical studies of defects producing fixed charge within Al(2)O(3) layers grown by atomic layer deposition (ALD) on In(0.53)Ga(0.47)As(001) substrates and the effects of hydrogen passivation of these defects. Capacitance-voltage measurements of Pt/ALD-Al(2)O(3)/n-In(0.53)Ga(0.47)As suggested the presence of positive bulk fixed charge and negative interfacial fixed charge within ALD-Al(2)O(3). We identified oxygen and aluminum dangling bonds (DBs) as the origin of the fixed charge. First-principles calculations predicted possible passivation of both O and Al DBs, which would neutralize fixed charge, and this prediction was confirmed experimentally; postmetallization forming gas anneal removed most of the fixed charge in ALD-Al(2)O(3). (C) 2010 American Institute of Physics. (doi:10.1063/1.3399776

Process Temperature Dependence of Al2O3Film Deposited by Thermal ALD as a Passivation Layer for c-Si Solar Cells

“…O ions near the interface increase, and O DBs might also increase after annealing. This could explain why the negative Q f increases after PMA [6,7]. …”

“…6 shows the atomic percentage of the Al2p and O1s peaks of the Al 2 O 3 film. In amorphous Al 2 O 3 , Al vacancies and O interstitials form oxygen dangling bonds (O DBs), which contribute to negative Q f [6,7]. In [7,8].…”

An investigation of capacitance-voltage hysteresis in metal/high-k/In0.53Ga0.47As metal-oxide-semiconductor capacitors

“…Due to the combination of a high electron mobility ($14 000 cm 2 /V s at low doping levels), suitable energy gap ($0.75 eV) and the fact that it can be grown lattice matched in InP, there has been a considerable focus of research attention on InGaAs with a 53% In concentration (i.e., In 0.53 Ga 0.47 As). The electrically active interface defects between the high-k gate oxide and the In 0.53 Ga 0.47 As surface, [7][8][9][10][11][12][13][14][15][16] and fixed charges within the high-k oxide, [15][16][17] have been studied in some detail in the literature. Charge trapping states can also be located in the transition region between the high-k oxide and In 0.53 Ga 0.47 As surface and are often referred to a "slow states" or "border traps".…”

Effect of low thermal budget annealing on surface passivation of silicon by ALD based aluminum oxide films

“…A negative shift (on abscissa) in the C-V curve with annealing confirms activation of positive fixed charges in the Al 2 O 3 film on InGaAs substrate. 42 Low thermal annealing is not very well explored besides observance of post-annealing activation of positive (+ve) charges. Only few publications reported activation of positive charges.…”