Engineered High Resistivity wafers with trap-rich layer

Okmetic Engineered High Resistivity SSP and DSP wafers combine low Oi and over 7,000 Ohm-cm resistivities with trap-rich layer. Thanks to this combination, the Engineered High Resistivity silicon wafers enable maximum RF device performance and very low insertion losses.

Okmetic Engineered High Resistivity silicon wafers are manufactured with Advanced Magnetic Czochralski (A-MCz®) crystal growth method and they combine low Oi and >7,000 Ohm-cm resistivity with engineered trap-rich layer. Tailored for the needs of RF filters and devices, this cutting-edge wafer technology reduces RF losses and provides stable “effective resistivity” over frequency range, resulting in higher Q values. The Engineered High Resistivity wafers also help improve linearity over temperature, minimize intermodular and second harmonics distortion, and reduce characteristic stress and bow. 

Engineered High Resistivity wafers provide superior performance in terms of 2nd harmonics and intermodular distortion, Insertion losses and Q-values

BAW filters and IPD devices among main usage areas

Engineered High Resistivity wafers are widely used in Bulk Acoustic Wave (BAW) filters and Integrated Passive Device (IPD) applications as the proprietary trap-rich layer enables high effective resistivity, very low insertion losses, superior 2nd harmonic values as well as excellent linearity over temperature. Other usage areas include integrated RFIC applications and silicon interposers, the both of which benefit from the very high and stable resistivity and superior electrical performance provided by customized High Resistivity wafers.

15 dB better IMD3 suppression than with the best known competing wafer technology and 80 dB second harmonics suppression overall

Optimized, superior performance and lower Total Cost of Ownership:

  • Excellent results observed in both IPD and BAW filter manufacturing.
  • The IMD3 (third order intermodulation distortion) suppression achieved with Engineered High Resistivity wafers is 15 dB better than with the best known competing wafer technology.
  • Overall 80 dB suppression in second harmonics (H2) levels with respect to temperature up to 100°C is achieved with Engineered High Resistivity wafers.
  • The engineered trap-rich layer can be tailored to match the specific customer process to maximize the gains in harmonic behavior and overall losses.
  • No need for complex implants and their effects on supply chain. The engineered trap-rich layer is purely silicon based providing a good match for the customers’ production lines as no foreign materials are involved.

Customized, Engineered High Resistivity solutions

Okmetic Engineered High Resistivity wafers are optimized, A-MCz® silicon wafers with low Oi, >7,000 Ohm-cm resistivity and engineered trap-rich layer to further minimize RF losses. These extremely high resistivities are enabled by Okmetic’s trademark Advanced Magnetic Czochralski (A-MCz®) crystal growth method. In addition to resistivities also other wafer parameters can be adjusted. The Engineered High Resistivity wafer selection includes 150 to 200mm SSP and DSP silicon wafers doped with either Boron or Phosphorus. Crystal orientations include <100> and <111> and thicknesses range from 380 to >1,150 µm.  

Typical RFSi® wafer specifications

Growth methodMCz, A-MCz®
Diameter150mm, 200mm
Crystal orientation<100>, <111>
N type dopantsPhosphorus
P type dopantsBoron
ResistivityUp to > 7,000 Ohm-cm
SSP wafer thickness150mm: 400 to 1,150 µm; 200mm: 550 to 1,150 µm
DSP wafer thickness 150mm: 380 to >1,150 µm; 200mm: 380 to >1,150 µm*
*Other thicknesses possible with certain limitations
Back surfacePolished, etched
DopantOrientationThicknessResistivityOxygen content
(ASTM F121-83)
Boron<100>380 – ≥ 1,150 µm
>5,000 Ohm-cm
>7,000 Ohm-cm
<10 ppma, MCz
<5 ppma, A-MCz®
Boron <111> 380 – ≥ 1,150 µm
> 5,000 Ohm-cm
> 5,000 Ohm-cm
<10 ppma, MCz
<5 ppma, A-MCz®
Phosphorus <100> 380 – ≥ 1,150 µm
> 500 Ohm-cm
> 500 Ohm-cm
<10 ppma, MCz
<5 ppma, A-MCz®

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