High Resistivity wafers

Okmetic High Resistivity SSP and DSP wafers combining low Oi and very high and stable resistivity enable improved electrical performance and reduced insertion losses of RF filters and devices.  

Okmetic 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. The High Resistivity wafers provide very high and stable resistivity, good electrical performance as well as reduced insertion losses.

Very high and stable resistivity, good electrical performance and reduced insertion losses

Okmetic High Resistivity silicon wafers are a good match for the needs of many BAW / SAW filter, IPD, silicon interposer and RFIC application types. In case RF manufacturers are looking for even higher performance and record-low losses, Okmetic Engineered High Resistivity wafers with added trap-rich layer will help achieve these things.

High Resistivity wafer benefits:

  • High, stable resisitivity
  • Good electrical performance
  • Reduced insertion losses
  • Reduced characteristic stress and bow, mechanically stronger wafers

High resistivity with customized wafer parameters

Okmetic High Resistivity wafers are optimized, A-MCz® silicon wafers with low Oi and up to >7,000 Ohm-cm resistivity. In addition to resistivities also other wafer parameters can be adjusted. The 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. The thin High Resistivity wafers enable more economical device integration in Wafer Level Packaging of silicon interposers. Also TSV (Through Silicon Vias) can be incorporated to them to further enhance the vertical packaging options.

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®

Replace FZ substrates with a more robust and cost-effective solution

Okmetic High Resistivity RFSi® wafers are manufactured with the Advanced Magnetic Czochralski (A-MCz®) method. They provide a superior alternative to High Resistivity silicon wafers manufactured with the FZ (Float Zone) method. Lower Total Cost of Ownership is achieved through lower purchase prices, higher production volume and availability, better performance, improved integration possibilities, and lower fab handling costs. The High Resistivity MCz wafers are mechanically stronger and less vulnerable to thermal stress, thereby reducing dislocations, warp, fractures, and the associated fab and assembly wafer yield losses. 

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