A novel high performance TFS SJ IGBT with a buried oxide layer

A novel high performance trench field stop （TFS） superjunction （S J） insulated gate bipolar transistor （IGBT） with a buried oxide （BO） layer is proposed in this paper. The BO layer inserted between the P-base and the SJ drift region acts as a barrier layer for the hole-carrier in the drift region. Therefore, conduction modulation in the emitter side of the SJ drift region is enhanced significantly and the carrier distribution in the drift region is optimized for the proposed structure. As a result, compared with the conventional TFS SJ IGBT （Conv-SJ）, the proposed BO-SJ IGBT structure possesses a drastically reduced on-state voltage drop （gce（on）） and an improved tradeoff between gee（on） and turn-off loss （Eoff）, with no breakdown voltage （BV） degraded. The results show that with the spacing between the gate and the BO layer Wo = 0.2 μm, the thickness of the BO layer Lo = 0.2 μm, the thickness of the drift region Ld = 90 μm, the half width and doping concentration of the N- and P-pillars Wn = Wp = 2.5μm and Nn = Np = 3 × 10^15 cm^-3, the Vce（on） and Eoff of the proposed structure are 1.08 V and 2.81 mJ/cm2 with the collector doping concentration Nc = 1 × 10^18 cm^-3 and 1.12 V and 1.73 mJ/cm2 with Nc = 5 × 10^17 cm^-3, respectively. However, with the same device parameters, the Vce（on） and Eoff for the Conv-SJ are 1.81 V and 2.88 mJ/cm2 with Nc= 1 × 10^18 cm^-3 and 1.98 V and 2.82 mJ/cm2 with Nc = 5 ×10^17 cm^-3, respectively. Meanwhile, the BV of the proposed structure and Conv-SJ are 1414 V and 1413 V, respectively.

A novel terminal structure for total dose irradiation hardened of a P-VDMOS

Using positive surface charge instead of traditional γ-ray total dose irradiation, the electric field distribution of a P-channel VDMOS terminal has been analyzed. A novel terminal structure for improving the total dose irradiation hardened of P-channel VDMOS has been proposed, and the structure is simulated and demonstrated with a -150 V P-channel VDMOS. The results show that the peak current density is reduced from 5.51 × 10^3 A/cm^2 to 2.01 × 10^3 A/cm^2, and the changed value of the breakdown voltage is 2.5 V at 500 krad（Si）. Especially, using 60Co and X-ray to validate the results, which strictly match with the simulated values, there is not any added mask or process to fabricate the novel structure, of which the process is compatible with common P-channel VDMOS processes. The novel terminal structure can be widely used in total irradiation hardened P-channel VDMOS design and fabrication, which holds a great potential application in the space irradiation environment.

SPTC^+-IGBT characteristics and optimization

A novel advanced soft punch through（SPT） IGBT signed as SPTC-IGBT is investigated.Static and dynamic characteristics are simulated based on the 1200 V device structure and adopted technology.Extensive research on the structure optimization of SPTC-IGBT is presented and discussed.Compared with the structure of conventional IGBT,SPTC-IGBT has a much lower collector-emitter saturation voltage and better switching characteristics.Therefore it is very suitable for applications blocking a voltage higher than 3000 V.In addition,due to the improvement of switching speed achieved by using a thinner chip,SPTC-IGBT is also very competitive in 1200 V and 1700 V applications.