Abstract
Deposited boron layers fabricated by exposing silicon to diborane (B 2H6) gas in an atmospheric-pressure chemical vapor deposition reactor are investigated with respect to their electrical properties. At the applied temperatures from 500 °C to 700 °C, the deposition forms a nanometer-thick layer stack of amorphous boron (α-B) and boronsilicon compound (BxSiy), whereas the crystalline Si substrate is p-doped to depths below 10 nm, depending on the temperature and exposure time. The as-deposited layers can be used to fabricate high-quality p+n diodes with low series resistance and low saturation current values that are comparable with those of conventional deep p+ junctions. By investigating p-n-p structures with p+ B-deposited emitters, it is shown that the presence of the α-B layer increases the effective Gummel number of the diffused emitter up to about a factor of 60. The α-B layer is also demonstrated to be a stable and controllable supply of B for the formation of deep p-type regions by thermal drive-in.
Original language | English |
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Article number | 5447662 |
Pages (from-to) | 1269-1278 |
Number of pages | 10 |
Journal | IEEE Transactions on Electron Devices |
Volume | 57 |
Issue number | 6 |
DOIs | |
Publication status | Published - 1 Jun 2010 |
Externally published | Yes |
Keywords
- Boron (B)
- Chemical vapor deposition (CVD)
- Diborane(BH)
- Doping
- Emitter
- Gummel number
- P-n-p bipolar transistor
- Pn diode
- Solid-phase diffusion
- Transient-enhanced diffusion (TED)
- Ultrashallow junctions