Effect of rapid thermal annealing on the barrier height of metal-GaAs with selenium interfacial layer

Low resistance Al nGaAs ohmic contacts

“…The experimental results presented in this paper can be explained in the following way. In many papers, a significant reduction of the Al-nGaAs Schottky contact effective barrier height has been reported as a result of the chalcogenide chemical (in various solutions) and physical (in vapour stream of group VI elements) treatments of an nGaAs surface [9][10][11][12][13][14][15][16][17]. Annealing at 400-550 • C leads to the further decrease of effective barrier height [12,13] and even to the formation of ohmic contacts, as shown in this paper.…”

“…Summarizing the works of different authors, the effective barrier height of the Se-treated Al-nGaAs Schottky contact barrier height (without any annealing) can vary from 0.36 eV [15] to 0.6 eV [17]. In [14] a substantial decrease of the effective barrier height of Se-treated Al-nGaAs Schottky contacts was observed only after annealing. However, the formation of ohmic contacts has not been observed in many studies on chalcogenide-treated A3B5 surfaces; sometimes these were unnoticed because of a wrong interpretation of 'very low Schottky barrier' IV presented in semilogarithmic scale.…”