Wafer fused p-InP/p-GaAs heterojunctions

Abstract

This article reports on the fabrication and characterization of wafer fused heterojunctions between p-InP and p-GaAs. Secondary ion mass spectroscopy was used to characterize doping profiles across the interface as well as the interface contamination with oxygen or carbon. The crystalline quality of the fused material was characterized using cross section and plan-view transmission electron microscopy. The electrical properties of the fused interface were studied as a function of various doping elements such as Be and Zn in InP or Zn and C in GaAs as well as for different acceptor concentrations in GaAs. Finally, the electrical characteristics were analyzed using a numerical model that includes thermionic emission and tunneling across the heterobarrier.

Improved electrical properties of wafer-bonded p-GaAs/n-InP interfaces with sulfide passivation

“…The interfacial conductivity of n-n and p-p heterojunctions was found to be improved by an increase in doping concentrations, bonding temperature, and removal of oxygen at the interfaces. [9][10][11] We previously fabricated a GaAs/InGaAs tandem solar cell by utilizing a direct bonding of n-GaAs/ n-InP. 11 In this structure, a heavily doped layer for the tunnel diode was grown on the GaAs structure to switch polarity for the bonded interface.…”

Electrical modeling of the GaAs/InP wafer bonded heterojunction

“…Wafer bonding heterostructures were achieved with ntype III-V compounds at usual doping level around 2x10 18 …”

“…It is a type II or staggered heterojunction particularly used as an electronic guide in order to force the flowing direction of the majority carriers, typically electrons from GaAs to InP [23]. For instance, for doping density around N d =10 18 cm -3 , electrons spread over a distance of approximately 1nm and consequently the space charge is localized very close to the interface. The electrostatic equilibrium at the interface, governed by the Poisson equation, is depending on the conduction band offset ΔE C .…”

“…It has been shown that thermionic emission as well as tunneling were both useful to achieve good agreement with experi-mental results. In the case of the GaAs/InP direct bonded junctions, Salomonsson et al were the first to fit the I(V) curves with the assumption of interface charges [18]. Other studies generally used energy band diagram calculations to explain experimental measurements but without fitting measurement with modeling predictions [10].…”

Growth of InP on GaAs (001) by hydrogen-assisted low-temperature solid-source molecular beam epitaxy

“…[3][4][5][6] However, there is a large lattice mismatch ͑3.8%͒ between InP and GaAs, which makes the heteroepitaxy very difficult. 7,8 Matthews and Blakeslee's theoretical expression 9 predicts that the critical thickness for a 3.8% lattice mismatch is lower than 5 nm. Numerous threading and misfit dislocations will come about once the critical film thickness is reached, thus hindering the realization of well-performing devices.…”