Temperature coefficient of on-state breakdown in InP- and GaAs-based heterostructure FETs

The breakdown measurements of GaAs-based and InP-based III-V devices measured in pulsed and DC conditions are presented. We will show that on-state breakdown voltage in InP-based HEMTs and GaAs HFETs has an opposite behavior as a function of the temperature. When increasing the temperature the breakdown voltage decreases in InP-based HEMTs while it increases in GaAs-based devices. This is due to the different thermal coefficient of the electron multiplication factor in InP- and in GaAs-based heterostructure FETs. This makes the design of power devices lattice matched on InP a challenge since the breakdown performance degrades when increasing the operating temperature. We will also show that DC measurements are not the right technique for evaluating on-state breakdown of power MESFETs and HEMTs since device self heating can induce wrong results. We propose pulsed measurements as a viable alternative