基于超结结构的肖特基势垒二极管

在功率半导体器件中,高的反向击穿电压和低的正向导通电阻之间的矛盾关系是影响其发展的主要因素之一,选用超结结构替代功率半导体器件中的传统电压支持层能够有效缓解这一矛盾关系。该文设计和实现了一种超结肖特基二极管,其中的电压支持层采用P柱和N柱交替构成的超结结构。在器件的制作方面,选用成熟的单步微电子工艺,通过4次N型外延和4次选择性P型掺杂来实现超结结构。为便于对比分析,设计传统肖特基二极管和超结肖特基二极管的电压支持层厚度一致,且超结结构中P柱和N柱的杂质浓度均和传统肖特基二极管的电压支持层浓度一致。测试得到传统肖特基二极管的反向击穿电压为110 V,而超结肖特基二极管的反向击穿电压为229 V。表明采用超结结构作为功率半导体器件的电压支持层能够有效提高反向击穿电压,同时降低器件的正向导通电阻,并且当P柱区和N柱区内的电荷量一致时器件的击穿电压最高。

Schottky Barrier Diode Based on Super-Junction Structure

The contradiction between higher reverse breakdown voltage and lower conduction resistance is important for power semiconductor devices. Using Super-Junction structure as the voltage support layer can weaken this contradiction. In this paper, a super-junction Schottky barrier diode (SJ-SBD), in which a SJ structure was used as the voltage support layer, was designed and fabricated. The SJ layer which is composed of alternant P-pillar and N-pillar was formed through four times N-type epitaxy and four times P-type implant. SJ-SBD and traditional SBD With the same thickness of drift layer were implemented. And the impurity concentration of P-pillar and N-pillar in SJ layer was the same as that of the drift layer in SBD. The tested results showed that the maximum reverse breakdown voltages are 110 V for traditional SBD and 229 V for SJ-SBD. It is indicated that using the SJ structure as the drift layer could increase the reverse breakdown voltage and reduce the conduction resistance obviously. And the breakdown voltage of SJ-SBD was the maximal when total charge in N-pillar and P-pillar was equal.