R. K. Lowry

Observation and electronic characterization of ‘‘new’’ E′ center defects in technologically relevant thermal SiO2 on Si: An additional complexity in oxide charge trapping

Using electron‐spin resonance (ESR), we demonstrate that several E’ variant precursors exist in a variety of technologically significant thermally grown thin SiO2 films on Si. The E’ variants include two varieties with the ubiquitous Eγ’ line shape (zero‐crossing g=2.0005, O3≡Si⋅) and a second very narrow line shape (zero‐crossing g=2.0019, structure unknown). We tentatively label the g=2.0019 defect EP for provisional E’ and distinguish the Eγ’ variants Eγn’ (neutral) and Eγp’ (positive). We combine ESR, capacitance versus voltage electrical measurements, and charge injection sequences to compare the electronic properties of the defects. We find that paramagnetic EP defects are positively charged while paramagnetic Eγ’ centers can be either positively charged or, under some circumstances, neutral. We find that EP precursors have a very large capture cross section for holes (σ=10−13 cm2) and that paramagnetic EP defects have an even larger capture cross section for electrons (σ=10−12 cm2). Both EP capture...

Observation and electronic characterization of two E’ center charge traps in conventionally processed thermal SiO2 on Si

We demonstrate that at least two varieties of E’ defect precursors exist in a wide variety of conventionally processed thermal SiO2 thin films. We provisionally label the defects EP and E’γp. We find that EP defect capture cross sections exceed the corresponding E’γp values by an order of magnitude, that EP centers are distributed far more broadly throughout the oxides than are the E’γp defects, and that the EP resonance, unlike the E’γp resonance is not stable at room temperature.

Electron‐spin‐resonance evidence for an impurity‐related E’‐like hole trapping defect in thermally grown SiO2 on Si

Using electron spin resonance (ESR), a new electrically active point defect in thermally grown SiO2 films on Si has been detected. The defect has a large capture cross section for electrons when it is paramagnetic and holes when it is diamagnetic (ESR inactive). The g‐tensor values, symmetry, and microwave power saturation characteristics are all similar to those of the well‐known E’ family of amorphous SiO2 defect centers.

Leakage currents and silicon dangling bonds in amorphous silicon dioxide thin films

Abstract We use electron spin resonance and current density versus electric field measurements to link silicon dangling bond defects, called E′ centers, to leakage currents in thin films of SiO2 on silicon.

Characteristics of a Surface Conductivity Moisture Monitor for Hermetic Integrated Circuit Packages

An in-situ surface conductivity sensor for measuring water content of hermetic package ambients is described. Results of correlation experiments with mass spectroscopy and volume-effect sensors are presented. Sensor studies of water desorption and contamination by leached ions are discussed. The surface conductivity sensor is well-suited to defining moisture levels within all types of hermetic packages.

A New Liquid Crystal for Field-Effect Viewing of 5V Vcc CMOS Logic Families

A novel liquid crystal for CMOS device diagnostics is discussed. The liquid crystal composition yields a threshold voltage of 1-2 Vrms and permits field-effect viewing of 5 volt logic families. Dark field illumination of cholesteric liquid crystals to provide wider temperature ranges for mapping hot spots is also discussed.

Enhancing reliability of CMOS devices using electrical techniques and electron spin resonance spectroscopy

Excessive failures due to threshold voltage shifts impacted the reliability of a CMOS analog comparator circuit. These shifts were attributed to a process-induced neutral hole trap. Electrical techniques were used to verify the model and determine the root cause. This work showed the need for a low cost technique for early defect detection which could be utilized during process development or as a process monitor. The method of electron spin resonance (ESR) was found to confirm the electrical results of this study. ESR is being developed as a diagnostic tool for improving product reliability.<<ETX>>

Evaluation of Critical Surface Cleanliness by Secondary Ion Mass Spectroscopy

Surfaces of a wide variety of IC materials, from raw silicon wafers to package piece parts, must be ultra-clean prior to key manufacturing steps to assure reliable performance of the finished devices. Knowledge of surface cleanliness is essential for optimum process design. Secondary ion mass spectroscopy (SIMS) is utilized to define levels of impurities on critical surfaces at various stages of device manufacture.