Methods of forming a self-aligned gate (SAG) and self-aligned source (SAD) device for high Ecrit semiconductors are presented. A dielectric layer is deposited on a high Ecrit substrate. The dielectric layer is etched to form a drift region. A refractory material is deposited on the substrate and dielectric layer. The refractory material is etched to form a gate length. Implant ionization is applied to form high-conductivity and high-critical field strength source with SAG and SAD features. The device is annealed to activate the contact regions. Alternately, a refractory material may be deposited on a high Ecrit substrate. The refractory material is etched to form a channel region. Implant ionization is applied to form high-conductivity and high Ecrit source and drain contact regions with SAG and SAD features. The refractory material is selectively removed to form the gate length and drift regions. The device is annealed to activate the contact regions.