A Study on the First‐Derivative Output Properties of GaN Static Induction Transistor with Submicrometer Fin Width

The first derivative of output curves of a Schottky‐junction vertical channel GaN static induction transistor (SIT) with a submicrometer‐sized fin is studied to understand its fundamental electrical properties. It is found that the derivative of output curves increases with the increase in drain voltage ( V ds ) in ohmic region because of the raised potential minima in the channel, which is not seen in SITs with a relatively long fin width. The influence of the gate voltages ( V gs ) and V ds on electric potential in the channel is demonstrated by evaluating the contribution of V gs and V ds , expressed through two coefficients α and β . The ratio of α to β increases up to 31.1 from 16.3 with decrease in the fin width from 0.9 to 0.5 μm, showing a higher dependency of the potential minima on V gs and the fin width. The voltage gain expressed by α / β is 14.9 dB for the GaN SIT with a fin width of 0.5 μm.