An electronic device can include a HEMT including at least two channel layers. In an embodiment, a lower semiconductor layer overlies a lower channel layer, wherein the lower semiconductor layer has an aluminum content that is at least 10% of a total metal content of the lower semiconductor layer. An upper semiconductor layer overlies the upper channel layer, wherein the upper semiconductor layer has an aluminum content that is greater as compared to the lower semiconductor layer. In another embodiment, an electronic device can include stepped source and drain electrodes, so that lower contact resistance can be achieved. In a further embodiment, an absolute value of a difference between pinch-off or threshold voltages between different channel layers is greater than 1 V and allows current to be turned on or turned off for a channel layer without affecting another channel layer.