An Attractive Wet Route for Nitriding III-Vs

The control of surface quality or interface chemistry is one of the key steps for a lot of new advanced industrial products with high added value. This is particularly true in the case of III‑V semiconductors (III-Vs) technology for which surface passivation plays a key role in device performances, low temperature and low damage processes having been developed over time to reduce surface effects.

With the introduction of III-V’s on large scale Silicon platforms and device scaling to nanometer range, passivation question will be on the front page again^[1]. Phosphorus nitride insulating films as passivation layers on InP seem to be very attractive to realize MISFETs with high channel electron mobilities and low interface state densities. This paper presents an original electroless approach of polyphosphazen film formation on InP in liquid ammonia (-55 °C). The chemical surface modifications are closed to those observed by electrochemistry[2],[3]. These findings are protected by a CNRS patent filed by us in 2013^[4]. Moreover, the chemical stability of the surface is also demonstrated by XPS analyses. Indeed no air ageing of the surface is observed after three months of air exposure. The electroless mode is attractive to the industry since it avoids any electrical (potential and current) control at the interface.

This paper proposes a novel electroless passivation route in liquid ammonia through a “Polyphosphazen like” film formation which could be adapted to a large scale production since no electrical contact is involved at the interface to provide a full and efficient chemical passivation.

 

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[1]“Interface engineering and chemistry of Hf-based high-k dielectrics  on III–V substrates”, G. He, X. Chen, Z. Sun, Surface Science Reports 68 (2013) 107.

[2] A-M. Gonçalves, N. Mézailles, C. Mathieu, P. Le Floch, A. Etcheberry, « «Fully Protective yet functionalizable monolayer onto InP” Chemistry of Materials.22 (2010) 3114-3120.

[3] A-M. Gonçalves, C.Njel, C. Mathieu, D.Aureau, A. Etcheberry. « Phosphazene like film formation on InP in liquid ammonia (223K). Thin Solid Films 538 (2013) 21–24.

[4] “Polyphosphazène electroless sur semiconducteurs III-P”, réf CNRS 03024-01 BFF100427CG
A. Etcheberry, A-M. Gonçalves, C. Mathieu, J. Vigneron, N. Mézailles, P. Le Floch