Extraction of spatio-temporal distribution of power dissipation in semiconductor devices using nanosecond interferometric mapping technique

Abstract

A method for the extraction of power dissipation sources inside semiconductor devices on a nanosecond-time scale is proposed using a backside transient interferometric mapping technique. The two-dimensional power dissipation density is extracted from the time and space derivative of the measured optical phase shift. The method is applied to the analysis of moving current filaments in an electrostatic discharge protection device operating in the avalanche regime. It is found that the filament dynamics is governed by the negative temperature dependence of the impact ionization coefficient. The total power calculated from the optical measurements is in excellent agreement with the electrical input power.

Interaction of traveling current filaments and its relation to a nontrivial thermal breakdown scenario in avalanching bipolar transistor

“…effects using the transient interferometric mapping ͑TIM͒ method. 19 TIM is based on probing temperature-or free carrier concentration-induced changes in the semiconductor refractive index by a nonabsorbing infrared probing laser beam ͑1.3 m wavelength͒. The resulting phase change ⌬ in the probe beam is measured interferometrically by a Michelson interferometer.…”

“…In the present study the thermal component of ⌬ is dominant, representing a two-dimensional ͑2D͒ thermal energy density in the device. 19 A 2D TIM holographic interferometry method is used to capture thermal images of the whole device at one or two selected times during a single electrical pulse, with a 3 m space and 5 ns time resolution. 20,21 A two-beam interferometer with two probe beams, capable of recording single-shot thermal transients at two spatial positions simultaneously, is used for accurate determination of speed, timing, location, and power dissipation in CF ͑space and time resolution is 2 m and 0.5 ns, respectively͒.…”

Transient self-heating effects in multifinger AlGaN/GaN HEMTs with metal airbridges

“…The scanning Du(x) signal provides thus a heat map of the device. Moreover, TIM method allows also to extract the instantaneous 2D power density P 2D (x) distribution [11]. The P 2D (x) map can localize the position of the heating source.…”

“…The current and voltage waveforms were recorded using a digital oscilloscope. To investigate heat dissipation we use the TIM technique [10,11], where the device is scanned (synchronized with voltage pulses) from the polished backside using an infrared laser beam (see Fig. 1).…”

“…The airbridge technology is used in highpower HEMTs to connect parallel source contacts in a multifinger layout. We use the transient interferometric mapping (TIM) [10,11] and electrical experimental methods [4] combined with a 2D thermal model to analyze the transient temperature increase and thermal cross talk between the fingers. We investigate the role of the airbridge metal in the device thermal management.…”