Shallow angle implantation for extended trench gate power MOSFETs with super junction structure

Abstract

In this paper, we present a new deep trench power MOSFET with super junction structure in the drift region, which exhibits strongly improved a relationship between blocking voltage and on-resistance. An accurate control of impurity concentration of n drift region in the trench sidewall is important to achieve the proposed MOSFET.Thus, we also quantitatively analyzed shallow angle ion implantations into trench sidewall by using a macrosize trench model. It was found that 40% ions doped into the incident sidewall and 12% ions were re-implanted into the opposite sidewall at the incident angle of 10 degrees.

A Trench LDMOS Improved by Quasi Vertical Super Junction and Resistive Field Plate

“…13(b) and Fig. 13(c), the silicon is etched and an QVSJ structure is formed probably by the traditional thermal diffusion or the angle ion-implantation [39]. After that, a thin buffer layer of BCB, an RFP layer of SIPOS, and the trench dielectric of BCB are deposited in sequence as shown in Fig.…”

Theory and optimization of the power super junction device

“…2010 年通过深槽刻蚀和外延生长工艺实现了 V B 大于 700 V 的超结 VDMOS [63] . 在低功耗功率电子领域, 提出了一种在槽两侧壁采用小倾角离子注入形成的 超结 VDMOS 的工艺制造方法 [64] , 其 N 区或 P 区可 以做得很窄. 专利 [65,66] 中采用该方法可制备具有低 阻通道和高 K 介质的超结器件.…”

An oxide filled extended trench gate super junction MOSFET structure

“…The SJ in new trench gate SJ MOSFET structure can be implemented easily by using trench etching and shallow angle implantation, whose feasibility has been validated, [2] the formation of SJ only needs to control accurately the implantation dose of n pillar region, which offers more freedom to device fabrication. Comparatively, in conventional trench gate SJ MOSFET structure, the formation of SJ needs multistep epitaxy growth combined with ion implantation [1] or multiple ion implantation, [6] or trench-filling combined with trench etching and epitaxy growth.…”

“…In order to further reduce the conduction loss and switching loss of power MOSFETs in high frequency power switches application, a super junction (SJ) is introduced in power MOSFET structure. [1] And to obtain high frequency, an extended trench gate SJ MOSFET with polysilicon filled trench [2] and a planar gate SJ MOSFET with oxide filled trench [3] have been proposed in recent years. But these structures have hardly the better trade-off relations between the blocking, conducting and switching characteristics simultaneously.…”