The evolution of ferroelectricity in undoped-HfO2 thin films is systematically studied by controlling the deposition temperature during atomic layer deposition.

The internal field (E int ) in ferroelectric films is an important factor which can affect the reliability of practical devices utilizing two memory states which results from the remanent polarizations of ferroelectric films. In the current work, the E int in TiN/Hf 0.5 Zr 0.5 O 2 /TiN capacitors was controlled by changing the annealing atmosphere (N 2 , O 2 , and forming gas). The magnitude of negative E int in O 2 -annealed samples was the largest, whereas that in the forming gas-annealed sample was the smallest. The magnitude of E int can be understood based on the asymmetric distribution of oxygen vacancies near top and bottom TiN electrodes. Despite the large magnitude of E int , the two remanent polarizations can be reliably retained due to the large coercive electric field of Hf 0.5 Zr 0.5 O 2 films, and this is expected to be beneficial for application in semiconductor memory devices. During the repetitive electric field cycling for the wake-up process, the change in E int in O 2 -and forming gas-annealed samples showed the opposite tendency: the magnitude of E int in the O 2 -annealed Hf 0.5 Zr 0.5 O 2 film decreased, whereas that in the forming gas-annealed film increased. This difference is believed to be due to the redistribution of oxygen vacancies with electric field high enough for the migration of oxygen vacancies. The conduction mechanism of electrons through Hf 0.5 Zr 0.5 O 2 films was also examined, and the results fitted best with the Poole-Frenkel emission model with the shallow traps for all the samples with a reasonable optical dielectric constant value for Hf 0.5 Zr 0.5 O 2 .

We treated 32 displaced mallet finger fractures by a two extension block Kirschner-wire technique. The clinical and radiological outcomes were evaluated at a mean follow-up of 49 months (25 to 84). The mean joint surface involvement was 38.4% (33% to 50%) and 18 patients (56%) had accompanying joint subluxation. All 32 fractures united with a mean time to union of 6.2 weeks (5.1 to 8.2). Congruent joint surfaces and anatomical reduction were seen in all cases. The mean flexion of the distal interphalangeal joints was 83.1 degrees (75 degrees to 90 degrees ) and the mean extension loss was 0.9 degrees (0 degrees to 7 degrees ). No digit had a prominent dorsal bump or a recurrent mallet deformity. We believe that this technique, when properly applied, produces satisfactory results both clinically and radiologically.