Satoshi Kuboyama

Mechanism for single-event burnout of power MOSFETs and its characterization technique

A novel characterization technique for single event burnout (SEB) of power MOSFETs was developed. The technique is based on a pulse-height analyzer system for charge collection measurement with a modified charge-sensitive amplifier which has a very wide dynamic range. The data obtained by this technique give detailed information about the SEB mechanism of power MOSFETs. The experimental data suggested a position-independent charge collection mechanism along an ion track, and a new parameter for SEB hardness was proposed. >

Analysis of single-ion multiple-bit upset in high-density DRAMs

New types of multiple-bit upset (MBU) modes have been identified in high density DRAMs (16 Mbit and 64 Mbit). The identification of the mechanisms responsible for the new modes is based on detailed physical bit-map analysis.

Anomalous Charge Collection in Silicon Carbide Schottky Barrier Diodes and Resulting Permanent Damage and Single-Event Burnout

It was demonstrated that Silicon Carbide Schottky Barrier Diodes exhibited anomalous charge collection with heavy ion irradiation. Consequently, the permanent damage and Single-Event Burnout was observed in spite of no known current sustaining mechanism. A model for the mechanism was proposed based on the device simulation

Single-Event Damages Caused by Heavy Ions Observed in AlGaN/GaN HEMTs

It was demonstrated that several kinds of permanent damage were introduced by heavy ions in AlGaN/GaN HEMTs similar to SiC devices. A new mode of damage attributable to the transistor structure was also identified in addition to the damage observed similarly in SiC devices.

Characterization of Microdose Damage Caused by Single Heavy Ion Observed in Trench Type Power MOSFETs

It was demonstrated that anomalously large degradation observed in power MOSFETs was caused by a single heavy ion. It was identified as a microdose effect and successfully characterized by several parameters extracted from the experimental data.

Improved model for single-event burnout mechanism

We describe an improved model for single-event burnout (SEB) mechanism. The model includes the direct tunneling of carriers at the interface of epitaxial layer and substrate. Compared with our previous models, the new model is more successful in reproducing the voltage dependence of the collected charge when incident heavy ions strike the emitter area. The model clearly explains the reason why the emitter stripe region was more susceptible to SEBs.

Single-event burnout of epitaxial bipolar transistors

Single-Event Burnout (SEB) of bipolar junction transistors (BJTs) has been observed nondestructively. It was revealed that all the NPN BJTs, including small signal transistors, with thinner epitaxial layers were inherently susceptible to the SEB phenomenon. It was demonstrated that several design parameters of BJTs were responsible for SEB susceptibility. Additionally, destructive and nondestructive modes of SEB were identified.

Numerical analysis of single event burnout of power MOSFETs

The single event burnout (SEB) phenomenon of power MOSFETs has been analyzed using a numerical device simulator code. It is found that the vertical current along the ion track directly indices the forward bias state of the source/p-body junction. It is also found that the current is governed by the conductivity of the plasma column. For the second peak of the EPICS spectra, a position-independent charge collection mechanism was also explained by the vertical current along the ion track. Experimental data obtained with EPICS (energetic particle induced charge spectroscopy) were explained clearly. It was found that the avalanche multiplication was caused by the distortion of neutrality of the plasma column around the p-body/drain junction. Under the strong avalanche multiplication condition, it could be regenerative. The existence of Q/sub TH/ in EPICS spectra may be explained by the mechanism. The influence of the penetration range of the incident ions is discussed. >

Study of Latent Damage in Power MOSFETs Caused by Heavy Ion Irradiation

The latent damages were investigated for power MOSFETs irradiated by high LET heavy ions. It was demonstrated that the post irradiation leakage current in damaged gate oxide was determined by the initial gate stress after the irradiation and the damage was stable even after a million of gate stress repetition.

Single-event burnout of Super-junction power MOSFETs

The experimental results of single-event burnout (SEB) of super-junction power MOSFETs are reported for the first time in comparison with those of standard MOSFETs. Similar tendencies were observed from both results. While a super-junction MOSFET (SJ-MOSFET) has an attractive electrical performance such as low on-resistance and high breakdown voltage, the experiment demonstrated that there was no structural advantage in SEB tolerance.