Sensitivity study of the SiGe heterojunction bipolar transistor single event effect based on pulsed laser and technology computer-aided design simulation

The single event effect of a silicon–germanium heterojunction bipolar transistor(SiGe HBT) was thoroughly investigated. By considering the worst bias condition, the sensitive area of the proposed device was scanned with a pulsed laser.With variation of the collector bias and pulsed laser incident energy, the single event transient of the SiGe HBT was studied.Moreover, the single event transient produced by laser irradiation at a wavelength of 532 nm was more pronounced than at a wavelength of 1064 nm. Finally, the impact of the equivalent linear energy transfer of the 1064 nm pulsed laser on the single event transient was qualitatively examined by performing technology computer-aided design simulations, and a good consistency between the experimental data and the simulated outcomes was attained.

Acute abdomen caused by spontaneous rupture of degenerative hysteromyoma during pregnancy:A case report

BACKGROUND Hysteromyoma is not a rare tumor among pregnant women.During pregnancy,the symptoms caused by hysteromyoma can be improved through conservative treatment in most cases.However,in order to ensure the safety of mothers and children,surgeries are necessary in some special cases.CASE SUMMARY We report a case of pregnancy complicated with hysteromyoma red degeneration.The patient had peritonitis after sudden abdominal pain during the 20th week of pregnancy.Laparoscopic exploration suggested rupture and bleeding of hysteromyoma,which were improved after drainage and an anti-inflammatory treatment.A cesarean section was performed after full term.This case shows the complications of rupture after red degeneration of hysteromyoma during pregnancy.CONCLUSION We should be alert to rupture of hysteromyoma during pregnancy,and active laparoscopic exploration is essential to improve the prognosis of such patients.

Synergistic effect of total ionizing dose on single event effect induced by pulsed laser microbeam on SiGe heterojunction bipolar transistor

The synergistic effect of total ionizing dose（TID） on single event effect（SEE） in SiGe heterojunction bipolar transistor（HBT） is investigated in a series of experiments. The SiGe HBTs after being exposed to 60 Co g irradiation are struck by pulsed laser to simulate SEE. The SEE transient currents and collected charges of the un-irradiated device are compared with those of the devices which are irradiated at high and low dose rate with various biases. The results show that the SEE damage to un-irradiated device is more serious than that to irradiated SiGe HBT at a low applied voltage of laser test. In addition, the g irradiations at forward and all-grounded bias have an obvious influence on SEE in the SiGe HBT, but the synergistic effect after cutting off the g irradiation is not significant. The influence of positive oxide-trap charges induced by TID on the distortion of electric field in SEE is the major factor of the synergistic effect. Moreover, the recombination of interface traps also plays a role in charge collection.

Dependence of single event upsets sensitivity of low energy proton on test factors in 65 nm SRAM

In order to accurately predict the single event upsets （SEU） rate of on-orbit proton, the influence of the proton energy distribution, incident angle, supply voltage, and test pattern on the height, width, and position of SEU peak of low energy protons （LEP） in 65 nm static random access memory （SRAM） are quantitatively evaluated and analyzed based on LEP testing data and Monte Carlo simulation. The results show that different initial proton energies used to degrade the beam energy will bring about the difference in the energy distribution of average proton energy at the surface and sensitive region of the device under test （DUT）, which further leads to significant differences including the height of SEU peak and the threshold energy of SEU. Using the lowest initial proton energy is extremely important for SEU testing with low energy protons. The proton energy corresponding to the SEU peak shifts to higher average proton energies with the increase of the tilt angle, and the SEU peaks also increase significantly. The reduction of supply voltage lowers the critical charge of SEU, leading to the increase of LEP SEU cross section. For standard 6-transitor SRAM with bit-interleaving technology, SEU peak does not show clear dependence on three test patterns of logical checkerboard 55H, all＂ 1＂, and all ＂0＂. It should be noted that all the SEUs in 65 nm SRAM are single cell upset in LEP testing due to proton＇s low linear energy transfer （LET） value.

Sensitivity of heavy-ion-induced single event burnout in SiC MOSFET

The energy deposition and electrothermal behavior of SiC metal-oxide-semiconductor field-effect transistor(MOSFET)under heavy ion radiation are investigated based on Monte Carlo method and TCAD numerical simulation.The Monte Carlo simulation results show that the density of heavy ion-induced energy deposition is the largest in the center of the heavy ion track.The time for energy deposition in SiC is on the order of picoseconds.The TCAD is used to simulate the single event burnout(SEB)sensitivity of SiC MOSFET at four representative incident positions and four incident depths.When heavy ions strike vertically from SiC MOSFET source electrode,the SiC MOSFET has the shortest SEB time and the lowest SEB voltage with respect to direct strike from the epitaxial layer,strike from the channel,and strike from the body diode region.High current and strong electric field simultaneously appear in the local area of SiC MOSFET,resulting in excessive power dissipation,further leading to excessive high lattice temperature.The gate-source junction area and the substrate-epitaxial layer junction area are both the regions where the SiC lattice temperature first reaches the SEB critical temperature.In the SEB simulation of SiC MOSFET at different incident depths,when the incident depth does not exceed the device's epitaxial layer,the heavy-ion-induced charge deposition is not enough to make lattice temperature reach the SEB critical temperature.

Impact of neutron-induced displacement damage on the single event latchup sensitivity of bulk CMOS SRAM

Since the displacement damage induced by the neutron irradiation prior has negligible impact on the performance of the bulk CMOS SRAM, we use the neutron irradiation to degrade the minority carrier lifetime in the regions responsible for latchup. With the experimental results, we discuss the impact of the neutron-induced displacement damage on the SEL sensitivity and qualitative analyze the effectiveness of this suppression approach with TCAD simulation.

A Marked Increase in Obstetric Hysterectomy for Placenta Accreta

Background：Obstetric hysterectomy （OH） as a lifesaving measure to manage uncontrolled uterine hemorrhage appears to be increasing recently.The objective of this study was to determine the etiology and changing trends of OH and to identify those at particular risk of OH to enhance the early involvement of multidisciplinary intensive care.Methods：A retrospective study was carried out in patients who had OH in China-Japan Friendship Hospital from 2004 to 2014.Maternal characteristics,preoperative evaluation,operative reports,and prenatal outcomes were studied in detail.Results：There were 19 cases of OH among a total of 18,838 deliveries.Comparing the study periods between 2004-2010 and 2011-2014,OH increased from 0.8/1000 （10/12,890） to 1.5/1000 （9/5948）.Indications for OH have changed significantly during this study period with uterine atony decreasing from 50.0% （5/10） to 11.1% （1/9） （P 〈 0.05）,and placenta accreta as the indication for OH has increased significantly from 20.0% （2/10） to 77.8% （7/9） （P 〈 0.05）.Ultrasonography and magnetic resonance imaging （MRI） have been used to make an exact antepartum diagnosis of placenta accreta.A multidisciplinary management led to improved outcomes for patients with placenta accreta.Conclusion：As the multiple cesarean delivery rates have risen,there has been a dramatic increase in OH for placenta accreta.An advance antenatal diagnosis of ultrasonography,and MRI,and a multidisciplinary teamwork can maximize patients＇ safety and outcome.