Scanning ion deep level transient spectroscopy: I. Theory

Abstract

Theoretical aspects of a new technique for the MeV ion microbeam are described in detail for the first time. The basis of the technique, termed scanning ion deep level transient spectroscopy (SIDLTS), is the imaging of defect distributions within semiconductor devices. The principles of SIDLTS are similar to those behind other deep level transient spectroscopy (DLTS) techniques with the main difference stemming from the injection of carriers into traps using the localized energy-loss of a focused MeV ion beam. Energy-loss of an MeV ion generates an electron-hole pair plasma, providing the equivalent of a DLTS trap filling pulse with a duration which depends on space-charge screening of the applied electric field and ambipolar erosion of the plasma for short ranging ions. Some nanoseconds later, the detrapping current transient is monitored as a charge transient. Scanning the beam in conjunction with transient analysis allows the imaging of defect levels. As with DLTS, the temperature dependence of the transient can be used to extract trap activation levels. In this, the first of a two-part paper, we introduce the various stages of corner capture and derive a simple expression for the observed charge transient. The second paper will illustrate the technique on a MeV ion implanted Au-Si Schottky junction.

Simulation of impulse response degradation from irradiation induced trapping and recombination regions in an InGaAs on InP photodetector

“…Here we concentrate solely on distributing traps over the n-InGaAs junction where reasonable levels of trapped SC can be comparable to FIG. 57,67 The time-dependent rate equations defining balance for an electron concentration at a trap with density N t and energy level E t is simply ͑Color online͒ Reverse simulated dark current vs trap density for the recombination case.…”

Scanning ion deep level transient spectroscopy: II. Ion irradiated Au–Si Schottky junctions

“…(e) The principle of the dilution limit [44] also applies to SIDLTS analysis [6]. In DLTS on heavily damaged devices, transients are forced to be singly exponential by holding the capacitance constant and measuring dV /dt or by limiting analysis to samples with N t 0.1N + [45].…”

“…In DLTS on heavily damaged devices, transients are forced to be singly exponential by holding the capacitance constant and measuring dV /dt or by limiting analysis to samples with N t 0.1N + [45]. For device D, the peak defect density may be 50% or more of the dopant level leading to possible non-exponential behaviour due to the timedependence of the displacement current, dJ d (t)/dt [6,25]. For N t > 0.1N + , both dx d /dt and J d become time-dependent as reflected in the Q-transient.…”

Investigation of Deep Levels in Diamond Based Radiation Detector by Transient Charge Spectroscopy with Focused Heavy Ion Microbeam

“…Deep level transient spectroscopy (DLTS) is a technique that is widely used to investigate deep levels in semiconductors [3,4]; however, the conventional DLTS has some disadvantages for characterizing defects in devices with high-resistivity such as radiation detectors. On the other hand, another approach of deep level evaluation technique was proposed using the properties of radiation-induced pulse signal inside the radiation detector [5,6]. Several defect levels in 4H SiC substrate was measured from transient properties of charge induced by alpha particle with Alpha particle induced charge transient spectroscopy (APQTS) system [5].…”