A Schottky diode, i.e. a metal-semiconductor junction, is among the simplest yet fastest electronic components. The underlying general theory has been developed by Schottky for the stationary, i.e. DC case, where electronic transmission processes through or over the barrier are associated with reliable absorption on the opposite electrodes, resulting in rectification. When operating it at high frequency, it is well known that the RC timescale sets an extrinsic limit. We present a series of experiments that address even higher frequencies using the electrical fields provided by intense light pulses, thus exploring the so far unattainable intrinsic limitations of Schottky rectification. Using graphene as a metal and silicon carbide (SiC) as semiconductor, epitaxial graphene on 4H-SiC (0001) provides a monolithic and extremely robust Schottky diode. Its current-voltage characteristics can accurately be described by Schottky’s model . When driving such a diode at high frequency, an RC damping at around 400 GHz could be determined [1]. Notably, Schottky’s description is fully consistent from DC to this frequency range. Similar devices have been studied before under perpendicular incidence [2], where ultrafast coherent excitation-tunneling processes faster than femtosecond scales could be identified. Our approach to study rectification beyond RC limitations is to replace the electrical voltage by intense light fields as they occur in ultrashort pulses, which now are applied from the sidewall (see Fig. 1). SiC devices using epitaxial graphene are extremely well suited for this case, because of their robustness and high optical transparency. In a first series of experiments, we applied mid-IR pulses at frequencies of 14 THz up to 82 THz, hence well above the RC limits. In reverse bias, there is a clear electrical response to the applied light field, hence rectification. By comparison with Schottky’s model, we find good but not yet perfect agreement. This motivated us to revisit the tunneling process at fast timescales. When the transfer time of electron motion through the barrier is similar to the oscillatory motion of the barrier itself, a semiclassical correction to Schottky’s theory is straightforwardly derived that describes partly oscillatory motion of the electron and an incoherent recapture mechanism. With this correction and the DC parametrization of the diode, the rectification in our experiments can be accurately predicted [3]. We have now adapted the same experimental strategy to near-IR pulses, with a center frequency of 375 THz. Simultaneously, we have chosen a slightly lower Schottky barrier. The result is again a field driven current contribution, as identified by a carrier-envelope phase dependent contribution. It increases with an effective power law. In order to understand this behavior, the Schottky model with its balance of tunneling and absorption turns out to be inappropriate. Rather, a time-dependent Schrödinger equation, hence a fully coherent treatment catches the experimental characteristics. This crossover of the physical description can be understood by a Keldysh-parameter close to unity.