Change in crystalline structure and band alignment in atomic-layer-deposited HfO₂ on InP using an annealing treatment

Abstract

Changes in structural characteristics and band alignments of atomic-layer-deposited HfO 2 films on InP (001) as a function of annealing temperature and film thickness were investigated using various analytical techniques. After an annealing at temperatures over 500 8C, the HfO 2 films were converted into a fully crystalline structure with a tetragonal phase with no detectable interfacial layer between the film and the InP substrate. In-P-O states, produced by interfacial reactions, were increased during the post deposition annealing (PDA) process and oxides were detected in the surface region of the HfO 2 film, indicating that In and P atoms had out-diffused. The E g value of the as-grown HfO 2 film was found to be 5.80 AE 0.1 eV. After the PDA treatment, the optical band gap and valence band offset values were significantly affected by the interfacial oxide states between the HfO 2 film and InP substrate. Moreover, band bending in InP, due to negative space charges generated by an unstable P-rich interfacial state during atomic layer deposition process was decreased after the annealing treatment.

Al2O3 Passivation Effect in HfO2·Al2O3 Laminate Structures Grown on InP Substrates

“…The following equation is for possible thermodynamics in the formation of In 2 O 3 and AlPO 4 : Al species + O 2 (g) (at Al 2 O 3 –InP interface) → AlPO 4 + In 2 O 3 [Δ G ∼ (−59 kcal)] . In addition, the AlPO 4 [Δ G ∼ −1618.0 (kcal/mol)] state is more thermodynamically stable than In 2 O 3 [Δ G ∼ −198.6 (kcal/mol)] . As a consequence, AlPO 4 bonds can be generated at the Al 2 O 3 –InP interface and In 2 O 3 states can be decreased.…”

Bias-stress-stable sub-1.5V oxide thin-film transistors via synergistic composition of sol-gel quaternary high-k oxide dielectrics

“…Figure 2d-f depict the XRD patterns of each binary oxide lm with reference peaks for the representative crystalline phases for Al 2 O 3 ; JCPDS 88-0826 (hexagonal), 86-1410 (monoclinic); for HfO 2 , JCPDS 78 − 0050 (monoclinic), JCPDS 08-0342 (tetragonal); and for ZrO 2 , JCPDS 88-1007 (tetragonal), JCPDS 86-1451 (monoclinic) [41][42][43][44][45][46]. In contrast to AlO x , we demonstrated that both HfO x and ZrO x had polycrystalline structures owing to their low crystallization temperatures.…”

Crystallization of HfO2in InAs/HfO2core–shell nanowires

“…However, most of the investigations were carried out on Si wafers; only very few investigations were done on other substrates, e.g. Ge [12] or III-V [13][14][15][16][17], and/or nanostructures [18,19].…”