Electrical and Optical Modeling of 4H-SiC Avalanche Photodiodes

Abstract

Optimal physical models and material parameters for 4H-SiC avalanche photodiodes (APDs) were studied using a two-dimensional device simulation tool. In the models, we took account of temperature-dependent impact ionization and absorption coefficient as a function of wavelength. The absorption coefficient spectra derived in this work exhibited a rapid increase below ∼300 nm, which can be qualitatively incorporated into indirect and direct band transition models. The simulated characteristics were in good agreement with the measured characteristics.

Electrical and ultraviolet characterization of 4H-SiC Schottky photodiodes

“…Using the refractive index reported in [30] for 4H-SiC ( = 3 at 270 nm and 2.6 at 280 nm), the absorption coefficient, α, reported in [31] for 4H-SiC ( = 17000 cm −1 at 270 nm and 8000 cm −1 at 280 nm), the hole diffusion length L p = 2 m [5] and the depletion layer width, W, found from the capacitance-voltage measurements as a function of reverse bias, QE was calculated.…”

Analysis of temperature-dependent characteristics of a 4H-SiC metal-semiconductor-metal ultraviolet photodetector

“…Hence, hydrodynamic transport model is used to properly model electron transport, energy relaxation and calculate a spatial electron and lattice temperatures. Unlike the drift-diffusion model, a temperature-dependent hydrodynamic Canali model is selected for the high field saturation of the mobility, Table 1 Temperature-dependent model parameters used in this study [12,16,17] Parameters Unit Value β 0 1.23 β exp 0.17…”

“…It is important to utilize an appropriate impact ionization model since the MSM detectors are operated with the variation of temperature. The temperature-dependent impact ionization coefficients for electrons are given by [16] ( , ) exp .…”

“…It is noted that the dominating recombination mechanism in 4H-SiC is a non-radiative capture of carriers by mid-gap defects [20]. We consider the temperature-dependent carriers life times for electron in the course of Shockley-Read-Hall (SRH) recombination, which can be described by [16] 0 , ref…”

“…With temperature-dependent physical model, an investigation of dark current variation at elevated temperature is carried out via a two-dimensional (2D) device simulator ISE-DESSIS. For the optical features at wide range of temperature, we address an exploratory method to extrapolate the UV absorption coefficients at different temperatures with consideration of the effects of variant phonon population, bandgap narrowing and direct band transition [16]. Finally, the calculated results are verified with relevant experiment and the electrical and optical characteristics of the MSM detector above room temperature (RT) are discussed in detail to evaluate thermal stability for practical application.…”