InSb is an important Ⅲ-Ⅴnarrow gap compound semiconductor material. It is widely used in optoelectronic devices manufacture especially mid-wave infrared detectors. With the application of ICP etching in large-scale InSb IRFPA detectors fabrication process, the influence of ICP etching induced damage on InSb IRFPA devices has been paid more attention. Surface states which reflect the characteristics of semiconductor surface play an important role in the study on etching damage of semiconductor materials. In this paper, the surface state density on three InSb samples: one sample without etching, one sample etched by ICP and another sample wet etched by lactic acid/nitric acid etchant after ICP etching, is tested and calculated by quasi-static C-V method. The characterization and removal of ICP etching induced damage are investigated. Furthermore, the method of testing and calculating the distribution of surface state density has been presented detailedly in this paper. This work plays a significant role in the development of large-scale InSb IRFPA detectors.
Thermal annealing effect on electrical properties of the Pt/Al0.45Ga0.55N Schottky contacts is investigated. The ideality factor, barrier height, and series resistance are obtained from the forward I-V characteristics of the Pt/Al0.45Ga0.55N Schottky contacts. For the Schottky contacts without annealing, the ideality factor decreases from 1.77 to 1.50, and series resistance decreases from 213 Ω to 126 Ω, and the barrier height increases from 1.00 to 1.18 eV with increasing temperature. For the Schottky contacts annealed in nitrogen ambient at 450°C for 1 min, the ideality factor decreases from 2.18 to 1.58, and series resistance decreases from 363 Ω to 207 Ω, and the barrier height increases from 0.77 to 1.04 eV with increasing temperature in a temperature range of 198-298 K. The ideality factor and series resistance of the Schottky contacts with annealing are higher than those without annealing, while the barrier height is lower than that without annealing at various temperatures. Variation of the ideality factor with temperature is good agreement with TFE theory. TFE theory analysis shows that the characteristic energy of 36.0 meV for the Schottky contacts with annealing is greater than 19.3 meV for that without annealing, which should be attributed to much more N vacancy produced at the interface between Pt and Al0.45Ga0.55N as a donor impurity due to annealing.
Au-Al0.30Ga0.70N Lateral Schottky photodiode was fabricated by an electrical breakdown of a single Schottky barrier of
metal-semiconductor-metal Au-Al0.30Ga0.70N film rocking curves are about 523.7 arcsec for the (00.2) plane reflection and about 989.5 arcsec for the (10.5) plane reflection. Dark
current of the device is 1.2nA at the reverse bias of 1 V at room temperature. Analysis of the measured characteristics
showed the ideality factor n, the zero-bias barrier height ΦB0 and the serial resistance RS are equal to 1.8, 0.80eV and
9.8KΩ, respectively. Ideality factor away from 1 and reverse leakage currents can be attributed from crystalline defects
in the materials.
Platinum was deposited on unintentionally doped n-AlxGa1-xN films grown by metal-organic chemical vapor deposition (MOCVD) to form MSM ultraviolet photodetectors. All devices were annealed for 10 min at different temperature in N2 ambient. Results indicate that the generation of hillocks on the surface of Pt thin-film electrodes at the elevated temperatures due to relieving compressive stress affects the dark current directly. Dark current less than 10pA in the (-10V,10V) range was obtained from a device after annealing at 900°C. Both detectors show sharp spectral responsivity cutoff of about three orders of magnitude by 325nm and 315nm respectively.