This paper presents the electric behavior of Δ-channel SOI nMOSFET transistors (triangular channel), as a function of the channel geometric dimensions, such as the channel length (L) and the internal angle (θ) of the triangular structure, in the drain leakage current (IDleak) behavior, for these devices operating since room temperature up to 300ºC. Through three-dimensional numeric simulations it was observed that IDleak is composed mainly by electrons, in all analyzed devices operating at high temperatures. Besides that, as L reduces, it was noticed that IDleak increases. However, for smaller angles θ, result smaller IDleak values, when the transistors are operating at same bias and temperature conditions.