Investigation of drain current transient in InP-based high electron mobility transistors (HEMTs)

Interface/surface states creation during device fabrication and device operation such as HC injection has been recognized as a major reliability issue in InPbased submicron HEMTs. It has been observed that the fabrication process or hot carriers have a marked influence on the dc and rf performance of InAlAs/InGaAs devices and have been comprehensively investigated [1-3]. It is generally accepted that the performance degradation is due mainly to the interface/surface states generation and recombination. Despite this, the fundamental understanding of the interface/surface state properties such as the trap energy level and time constant are still lacking. In this work, a simple technique based on the measurement of the transient drain current is demonstrated for quickly assessing the properties of the HC-induced traps. Two different kinds of interface traps with distinctive time constants have been measured in our present devices.