Formation of a ZnO/ZnS interface passivation layer on (NH₄)₂S treated In_0.53Ga_0.47As: Electrical and in-situ X-ray photoelectron spectroscopy characterization

Abstract

Atomic layer deposition is used to convert an (NH4)2S cleaned p-In0.53Ga0.47As with diethylzinc (DEZ) and water, resulting in the formation of a ZnO/ZnS interfacial passivation layer (IPL). The process is studied using in-situ X-ray photoelectron spectroscopy. DEZ reacts with sulfur and oxygen present on the surface, chemically reducing arsenic 3+ and gallium 3+ to lower oxidation states. The sulfur concentration remains constant during the deposition process while the oxygen concentration on the surface remains small, confirming that the IPL is composed of both ZnO and ZnS. Measurements of metal–oxide–semiconductor capacitors with HfO2 for the dielectric show that the ZnO/ZnS IPL can nearly eliminate frequency dispersion (<1% per frequency decade) in accumulation and results in small hysteresis (<60 mV) with a D it in the 1011 eV−1 cm−2 range in the midgap. Frequency dispersion is observed in the depletion region and is attributed to minority carrier generation from the ZnO present in the IPL.

Brief Review of Surface Passivation on III-V Semiconductor

“…ZnS has better thermochemical stability and higher band gap energy than ZnO [36], which makes it an attractive and promising candidate as an interface passivation layer (IPL) material in III-V based devices. Lucero et al used ALD to format a ZnO/ZnS IPL by converting an (NH4)2S cleaned p-In0.53Ga0.47As with diethylzinc and water [37]. Diethylzinc reacted with S and O on the InGaAs, ZnO wideband material has attracted increasing attention in the passivation field.…”

Property Improvement of GaAs Surface by 1-Octadecanethiol Passivation

“…Controlling the chemical and electronic properties of the III-V semiconductor surface/interface by a passivation method is a theme that has been studied extensively in the fields of semiconductor lasers [1,2], metal-oxide-semiconductor field effect transistors [3,4], and solar batteries [5] for several decades. Among various methods, sulfur passivation, e.g., using CH 3 CSNH 2 , (NH 4 ) 2 S·9H 2 O, S 2 Cl and Na 2 S [6][7][8] aqueous or organic solutions, have been reported widely due to their simplicity and effectiveness. They can reduce the GaAs surface state density by removing Ga-O/As-O bonds and then saturate the dangling bonds with S-.…”

Effects on the Surface and Luminescence Properties of GaAs by SF6 Plasma Passivation

“…In this work, we report fluorine and sulfur plasma incorporation on GaAs surfaces by a glow discharge in SF 6 ambience. Because of the high electronegativity of fluorine ions, it may substitute oxygen vacancy sites and dangling bonds on GaAs surfaces.…”

“…The traditional passivation for GaAs is mainly based on wet passivation by sulfur-containing solutions [4][5][6][7], which can form a thin layer of sulfide to saturate part of the dangling bonds, and to remove native oxides on GaAs surfaces effectively. Although this passivation method can reduce the surface nonradiative recombination, the thin sulfur passivation layer is not stable in an atmospheric environment and the passivation effect will obviously degrade in a short period of time.…”