Reduced surface electron accumulation at InN films by ozone induced oxidation

Abstract

A room temperature ozone induced oxidation of thin InN films is proposed to improve the electric transport properties. The sheet carrier density is reduced upon oxidation by a value which is in the order of the electron concentration of an untreated InN surface. Thus, ozone effectively passivates the surface defect states on InN and might be an effective method to prepare InN films for electronic applications. A model for the improved electron transport properties is proposed taking into account the decreased surface band bending and the decreased influence of surface electrons on the net mobility of InN layers.

Electron transport properties of indium oxide – indium nitride metal‐oxide‐semiconductor heterostructures

“…The downward band bending was varied in reasonable limits bearing in mind the value -0.9 eV with respect to the Fermi level in bulk InN. 13 These results are depicted in Fig. 4.…”

“…[13] Among the mechanisms determining the apparent concentration of carriers, the accumulation of electrons at the InN surface was found to be manipulated by the formation of a thin surface oxide layer. The reduction of the net carrier density of the InN epilayer (Fig.…”

“…by formation of a thin indium oxide surface layer. Recently, many efforts have been made on the oxidation of InN, which is indispensable for the fabrication of HFET structures [11][12][13]. In particular, body centred cubic (bcc-) In2O3 has a band gap of ~ 3.7 eV and a static dielectric constant of ~ 9 [14], and therefore is an appropriate gate dielectric material for fabrication of high-frequency InN-HFET.…”

Synthesis and Properties of High-Quality InN Nanowires and Nanonetworks

“…It has been recently observed that In 2 O 3 layers grown on InN can enhance the carrier mobility. 24 Since the InN NWs reported in this study are covered with a thin shell of In 2 O 3 , this could also be a possible reason for the increased mobility compared to earlier studies. However, it should be noted that the mobility of the carriers in the InN NWs is still much lower than the carrier mobility of 1000 to 3000 cm 2 /V s measured in thin films.…”

Ozone and UV assisted oxidation of InN surfaces

“…Previous studies have shown, that the high electron concentration consists of different contributions [4,5]: (i) high electron sheet concentration at the surface and interface, which origin is still under investigation, (ii) a homogeneous background volume concentration and (iii) an inhomogeneous electron concentration over the InN film due to dislocations inside the film [6].…”