Analysis of different forward current–voltage behaviours of Al implanted 4H-SiC vertical p–i–n diodes

•The J–V characteristics of well behaved and leaky diodes in 4H-SiC are presented.•Almost all the diodes show good rectifying behaviours.•Experimental and simulation results are combined to extract key physical parameters.•The role of the diode internal resistance in determining a crossing point is discussed.•The simulated J–V characteristics are in good agreement with the experimental data.

In this work different experimental current–voltage behaviours of several Al implanted 4H-SiC p–i–n diodes are investigated by means of numerical simulations in a wide range of currents and temperatures. Some devices for which recombination and tunneling are the dominant current processes at all biases are classified as “leaky” diodes. The well behaved diodes, instead, show good rectifying characteristics with a current conduction due to tunneling below 1.7 V, recombination between 1.7 V and 2.5 V, and diffusion processes above 2.5 V. At higher current regimes, a series resistance in excess of 1 mΩ cm2 becomes the main current limiting factor. Depending on the relative weight between the contact resistances and the internal diode resistance, different temperature dependencies of the current are obtained. A good agreement between numerical and measured data is achieved employing temperature-dependent carrier lifetime and mobility as fitting parameters.