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We report on the investigation of random telegraph signals (RTSs) in pMOSFETs at variable temperatures to identify and characterize the hole traps residing at the oxide–semiconductor interface. Attractive center defects as well as a repulsive center defect are identified with trap location, capture cross section, remote Coulomb scattering coefficient, capture barrier energy, trap binding enthalpy, relaxation energy, and change in entropy with hole emission. The attractive centers responsible for RTS were a pair of dissociated three-coordinated silicon (D-III-Si) defects while the repulsive center was identified as a puckered/back-projected oxygen vacancy defect, [a pair of under-coordinated silicon (III-Si) and over-coordinated oxygen (III-O) defects]. Both contain ${E}\gamma ^{\prime }$ centers. This is the first time when such detailed analysis is reported on the hole traps in SiO2 which are responsible for RTS.

Random telegraph signals (RTS) have been used as a technique for gate oxide defect analyses for the last few decades. The time required by a gate oxide defect to capture and emit an inversion layer carrier can be used to extract the defect energy parameters. The RTS behavior measured at different temperatures can provide sufficient information to determine the structure and physical nature of the responsible defects. In addition, an RTS simulation tool is developed that can successfully reconstruct the RTS traces based on the trap parameters related to the defects. Application of electrical stress results in additional RTS in the output signal, which is believed to be the result of Si–Si bond breakage and creation of hole traps, or reactivation of passivated traps. Stressing the MOSFETs has also resulted in random activation and deactivation of oxide traps. This chapter focuses on the theoretical background of RTS in MOSFETs, sample setup for RTS measurements, data analyses, advantages, and limitations of using RTS to characterize defects.

The effect of channel hot carrier stress has been investigated in pMOSFETs with respect to channel hole trapping by the gate oxide traps and the resultant Random Telegraph Signals (RTS) observed at the output. Process- and stress- induced oxide traps have been identified through RTS measurements. These traps are believed to be E′ centers, acting as hole-attractive or repulsive centers, causing RTS through correlated carrier number and mobility fluctuations. Generation of E′ centers as well as activation of the passivated oxide defects as a result of stress are thought to be the reasons behind observing the stress-induced RTS. Two of the observed defects: one process-induced and one stress-induced trap have disappeared and reappeared randomly with stress. We report the reaction of the defects with hydrogen to be responsible for the volatile nature of the traps. Hydrogen is either bound to the Si/SiO2 interface or trapped at the oxide defects. Applying the stress releases these hydrogen species, which then drift towards the gate through the oxide layer and react with the oxide defects to passivate them. Reaction with another hydrogen de-passivates the defect releasing H2. This is the first article that reports hydrogen to deactivate and reactivate oxide traps responsible for RTS.

In recent times, the Type-II InAs/GaSb Superlatttice has been opted as a viable replacement for HgCdTe based photodetectors as the band structure of these devices can be tailored. Significant progress has been made and ongoing research is being conducted in the growth and characterization of these devices. We present the model of such a device with experimentally verified dimensions and parameters. The Transfer Matrix Method (TMM) has been adopted to represent the wave function solution under zero bias and non-zero bias respectively. Cutoff wavelength of 10µm range was achieved. These devices have the added advantage of tunability with respect to well width and bias voltages and have attractive applications in optical switching.