skip to main content

SciTech ConnectSciTech Connect

Title: Phosphorus and boron diffusion paths in polycrystalline silicon gate of a trench-type three-dimensional metal-oxide-semiconductor field effect transistor investigated by atom probe tomography

The dopant (P and B) diffusion path in n- and p-types polycrystalline-Si gates of trench-type three-dimensional (3D) metal-oxide-semiconductor field-effect transistors (MOSFETs) were investigated using atom probe tomography, based on the annealing time dependence of the dopant distribution at 900 °C. Remarkable differences were observed between P and B diffusion behavior. In the initial stage of diffusion, P atoms diffuse into deeper regions from the implanted region along grain boundaries in the n-type polycrystalline-Si gate. With longer annealing times, segregation of P on the grain boundaries was observed; however, few P atoms were observed within the large grains or on the gate/gate oxide interface distant from grain boundaries. These results indicate that P atoms diffuse along grain boundaries much faster than through the bulk or along the gate/gate oxide interface. On the other hand, in the p-type polycrystalline-Si gate, segregation of B was observed only at the initial stage of diffusion. After further annealing, the B atoms became uniformly distributed, and no clear segregation of B was observed. Therefore, B atoms diffuse not only along the grain boundary but also through the bulk. Furthermore, B atoms diffused deeper than P atoms along the grain boundaries under the same annealing conditions. This informationmore » on the diffusion behavior of P and B is essential for optimizing annealing conditions in order to control the P and B distributions in the polycrystalline-Si gates of trench-type 3D MOSFETs.« less
Authors:
; ; ; ;  [1] ;  [2] ;  [3] ; ;  [4]
  1. The Oarai Center, Institute for Materials Research, Tohoku University, 2145-2 Narita, Oarai, Ibaraki 311-1313 (Japan)
  2. Department of Electrical Engineering, Faculty of Engineering, Tokyo City University, 1-28-1 Tamazutsumi, Setagaya-ku, Tokyo 158-8557 (Japan)
  3. Renesas Semiconductor Manufacturing Co., Ltd., 1120 Shimokuzawa, Sagamihara, Kanagawa 252-5298 (Japan)
  4. Renesas Electronics Corporation, 751 Horiguchi, Hitachinaka, Ibaraki 312-8504 (Japan)
Publication Date:
OSTI Identifier:
22483204
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 2; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANNEALING; ATOMS; BORON; DIFFUSION; DISTRIBUTION; GRAIN BOUNDARIES; METALS; MOSFET; OXIDES; PHOSPHORUS; POLYCRYSTALS; SEGREGATION; SEMICONDUCTOR MATERIALS; SILICON; THREE-DIMENSIONAL CALCULATIONS; TIME DEPENDENCE; TOMOGRAPHY