High-Temperature Annealing Assisted High-Quality Semipolar (1122) AlN Film for Vacuum Ultraviolet Detectors
Yaqi Gao, Jiankun Yang, Lulu Wang, Yiwei Duo, Ziqiang Huo, Junxue Ran, Junxi Wang, Tongbo Wei
Abstract
High-temperature annealing (HTA) has been recognized as an available method to annihilate the domain boundaries and improve the crystalline quality of AlN films. Here, semipolar (112̅2) AlN films through the HTA process are utilized to prepare the vacuum ultraviolet photodetectors (VUV PDs). The resulting semipolar AlN films show full widths at half-maximum of the high-resolution X-ray rocking curves that are 527 and 622 arcsec along [112̅3̅] AlN and [11̅00] AlN, respectively, which illustrates much improved crystalline quality compared to previous reports. HTA not only renders markedly improved AlN quality but also reduces the in-plane anisotropic characteristic. The responsivities of regrown AlN PD and direct-grown-AlN PD are 2.23 and 1.33 A/W at 20 V, respectively. The improvement in the responsivity and specific detectivity of PDs is attributed to the reduction of crystal mosaicity and stacking faults of semipolar (112̅2) AlN using HTA technology. These results have confirmed that the HTA strategy is significant for the improvement of semipolar (112̅2) AlN films and VUV PDs.