OBIC Measurements on Avalanche Diodes in 4H-SiC for the Determination of Impact Ionization Coefficients

Abstract

Optical Beam Induced Current (OBIC) measurements have been performed on 4H-SiC avalanche diodes with very thin and highly doped avalanche region. The light source used in this study is an Ar-laser with a wavelength of 351 nm which results in a mixed carrier injection. From these measurements, impact ionization coefficients for 4H-SiC have been extracted in the electric field range from 3 to 4.8 MV/cm. In combination with ionization coefficients in our previous paper extracted from diodes with lowly doped avalanche region, we propose a set of parameters of impact ionization coefficients for 4H-SiC, applicable to a wide electric field range.

SIMS Analyses Applied to Open an Optical Window in 4H-SiC Devices for Electro-Optical Measurements

“…As an ultimate proof for the suitability of this method, the experimental extraction of the impact ionization coefficients in 4H-SiC has been performed from OBIC analyses on these diodes with an optical window opened by SIMS. More details on these results are presented in another paper in this conference [7].…”

Determination of 4H-SiC Ionization Rates Using OBIC Based on Two-Photon Absorption 

“…This solution works well, optical power remains high at this point and no scratches are observed on the DUT surface. The DUT is the same circular avalanche diode, with a breakdown voltage of 59 V, as already used in previous studies [5,6,8,12]. It presents a thin and highly doped active layer, which means high electric field devices (> 3 MV.cm -1 ).…”

Ανάπτυξη μικρομετρικών τρανζίστορ εγκάρσιου πεδίου από καρβίδιο του πυριτίου (SiC)

“…As for the rest, the references are the ones mentioned below. 4H-SiC physical property values references (clockwise): [18], [19], [20], [21], -, [22], [23], [11]. GaN physical property values references (clockwise): [24], [25], [26], [27], -, [28], [29], [30].…”

“…A series of experimental measurements [18], [19], [134], [108], [135], [136] and theoretical calculations [109], [137] been performed to determine the ionization rates of 4H-SiC. Most of them deal with transport along c-axis. )…”

“…Physical Parameters of SiC and corresponding models for TAD simulations perature for carrier transport parallel to c-axis, some [142], [19], [134] at different temperatures and very few [108], [109] and [143] for different crystal orientations. Most authors use the Chynoweth form [136], [108], [19] or the Selberherr relation, like in [134], for fitting the electric field variation of impact ionization coefficient. Few studies [18] and [137] use a "Thornber-like" model although incorporating mean free paths:…”