Trap effects in p-channel GaAs MESFET's

After processing of conventional n-channel GaAs MESFETs, traps in the channel and channel interface regions cause several deleterious parasitic device effects. It is known that a p-well GaAs MESFET structure eliminates all of the undesirable parasitic effects in n-channel devices; moreover, complementary p-channel MESFETs are realizable with the same p-well technology. The hole capture and emission processes of deep-level traps associated with p-channel GaAs MESFETs are characterized here using temperature-dependent drain current transient measurements. The transient behavior is dominated by trapping in the channel-substrate interface region analogous to an n-channel MESFET. By employing a one-level model to extract the activation energy and capture cross section, the traps in the channel-substrate region of the p-channel MESFET are attributed to an EL2 antisite defect (As/sub Ga/).<
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