Homogeneous transparent conductive ZnO:Ga by ALD for large LED wafers

Szabó, Zoltán and Baji, Zsófia and Basa, Péter and Czigány, Zsolt and Bársony, István and Volk, János (2016) Homogeneous transparent conductive ZnO:Ga by ALD for large LED wafers. APPLIED SURFACE SCIENCE, 379. pp. 304-308. ISSN 0169-4332

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Highly conductive and uniform Ga doped ZnO (GZO) films were prepared by atomic layer deposition (ALD) as transparent conductive layers for InGaN/GaN LEDs. The optimal Ga doping concentration was found to be 3 at%. Even for 4" wafers, the TCO layer shows excellent homogeneity of film resistivity (0.8 %) according to Eddy current and spectroscopic ellipsometry mapping. This makes ALD a favourable technique over concurrent methods like MBE and PLD where the up-scaling is problematic. In agreement with previous studies, it was found that by an annealing treatment the quality of the GZO/p-GaN interface can be improved, although it causes the degradation of TCO conductivity. Therefore, a two-step ALD deposition technique was proposed and demonstrated: a "buffer layer" deposited and annealed first was followed by a second deposition step to maintain the high conductivity of the top layer. © 2016 Published by Elsevier B.V.

Item Type: Article
Uncontrolled Keywords: Transparent conductive layer; Transparent conductive; Ingan/gan leds; High conductivity; Gadoped ZnO (GZO); Film resistivity; Deposition technique; Annealing treatments; Zinc oxide; spectroscopic ellipsometry; Semiconductor doping; Light emitting diodes; Eddy current testing; DEPOSITION; Conductive films; annealing; TCO; Rapid thermal annealing; LED; GZO; Atomic layer deposition
Subjects: Q Science / természettudomány > QD Chemistry / kémia > QD02 Physical chemistry / fizikai kémia
Depositing User: MTMT SWORD
Date Deposited: 07 Jun 2016 13:42
Last Modified: 07 Jun 2016 13:42

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