Atomic layer-deposited platinum in high-k/metal gate stacks

Abstract

Nanoscale platinum films are deposited by atomic layer deposition using trimethylmethylcyclopentadienyl-platinum and oxygen as precursors on the high-k dielectrics ZrO 2 and Al 2 O 3 , respectively, and on SiO 2 , issuing deposition temperature and precursor ratios. The ALD-grown platinum films are polycrystalline and show a preferential (1 1 1) orientation. The films are homogeneous with a root mean square roughness of 0.6-0.7 nm and reveal a low resistivity of 13.2 μ cm. The effective work functions are 4.76 eV for ZrO 2 , 5.22 eV for Al 2 O 3 and 5.52 eV for SiO 2 . It is remarkable that the deposition temperature of the platinum metal gate influences the final equivalent oxide thickness. Comparing both, PVD and ALD platinum films, a decreased leakage current density is observed for the ALD films depending on ALD process conditions, along with an increase in the equivalent oxide thickness.

Al2O3‐Atomic Layer Deposited Films on CH3NH3PbI3: Intrinsic Defects and Passivation Mechanisms

“…[7] We have previously studied the properties of Al 2 O 3 films prepared by thermal ALD (TALD) and plasma-enhanced ALD (PEALD). [8][9][10][11] We established that the electronic structure is dominated by intrinsic defect states within the electronic band gap including excitonic, polaronic, and charge-transfer (CT) defect states. [10,11] Their relative abundance depends on the choice of the used ALD parameters and substrate.…”

“…[8][9][10][11] We established that the electronic structure is dominated by intrinsic defect states within the electronic band gap including excitonic, polaronic, and charge-transfer (CT) defect states. [10,11] Their relative abundance depends on the choice of the used ALD parameters and substrate. [10,11] ALD allows the fabrication of very thin films with very accurate thickness control based on self-limiting surface reactions at low temperatures.…”

“…[10,11] Their relative abundance depends on the choice of the used ALD parameters and substrate. [10,11] ALD allows the fabrication of very thin films with very accurate thickness control based on self-limiting surface reactions at low temperatures. [12] A particular beneficial role of ALD for the perovskite-based PV applications is seen in its ability to use a reduced thermal budget [12] because organic layers often decompose at higher temperatures.…”

“…Such films are grown directly on the MAPI surfaces without pretreatment; in particular, there is no need for an OHcovered surface preparation. [10,[13][14][15][16] As a consequence, MAPIbased PV devices showed recently an increase in long-term stability and a protection against ambient conditions upon growth of ALD films of Al 2 O 3 at RT. [10,[14][15][16] Hence, the properties of such Al 2 O 3 films prepared at RT are of particular interest to improve the long-term stability of MAPI PV devices without losing device performances.…”

“…[10,[13][14][15][16] As a consequence, MAPIbased PV devices showed recently an increase in long-term stability and a protection against ambient conditions upon growth of ALD films of Al 2 O 3 at RT. [10,[14][15][16] Hence, the properties of such Al 2 O 3 films prepared at RT are of particular interest to improve the long-term stability of MAPI PV devices without losing device performances. Al 2 O 3 -coated MAPI films were investigated previously by resonant photoelectron spectroscopy (resPES) and compared with the TALD and PEALD Al 2 O 3 films fabricated at different process conditions and on different substrates as mentioned earlier.…”