I'm doing experiments with electric fields and would (ideally) like a very thin box as shown in this picture:

It would need a very thin \$h\$ (of about 200 um at most, if possible), an \$l\$ of about 10 cm and a \$w\$ that would allow a resistance of about 180 ohms. Since $$ R = \rho \frac{w}{h*l} $$

that would mean w would depend on the resistivity \$ \rho \$ of the material.

Also, it would really help if the top and bottom surfaces are covered with an even thinner insulator (~5 um would be possible? The smaller the better).

I was thinking about a silicon wafer. Some shops sell it with an \$ h ~ 130um \$, \$ \rho ~ 0.01 ohm * m \$ , \$ l ~10 cm\$ which would mean \$ w ~ 23cm\$. But if \$ \rho \$ is even smaller than better (as long as \$ l > 1cm \$ its good so I can still work on it with my hands)

But I never bought a wafer before and dicing it (a "circular" wafer doesn't suit me at all) seems to be nontrivial, specially for more or less precise (< 30% error) cuts and unfortunately I'm not so handy (I think I will break most of them)...

Also, I saw that we can purchase the wafer with a coating but as far as can tell (which maybe is wrong), its not just for the top and bottom sides, the coating would reach every side of the wafer. Since I want to plug in a power supply to the front and back sides of the wafer, these sides need to be "accessible". Even without coating, I don't know if it possible to solder some wire directly into the silicon to connect it to the power supply...?

Is there a better idea than the wafer? If the wafer is a "good" solution, can you recommend some (European would help) manufacturer?

Also, please keep in mind that is a hobby experiment, not an application and certainly not for a commercial system so I can spend some money, but not $1000 :).

I'm doing experiments with electric fields and would (ideally) like a very thin solid box (not hollow) as shown in this picture:

It would need a very thin \$h\$ (of about 200 um at most, if possible), an \$l\$ of about 10 cm and a \$w\$ that would allow a resistance of about 180 ohms. Since $$ R = \rho \frac{w}{h*l} $$

that would mean w would depend on the resistivity \$ \rho \$ of the material.

Also, it would really help if the top and bottom surfaces are covered with an even thinner insulator (~5 um would be possible? The smaller the better).

I was thinking about a silicon wafer. Some shops sell it with an \$ h = 130um \$, \$ \rho = 0.01 \Omega m \$ , \$ l = 10 cm\$ which would mean \$ w = 23cm\$. But if \$ \rho \$ is even smaller than better (as long as \$ l > 1cm \$ its good so I can still work on it with my hands)

But I never bought a wafer before and dicing it (a "circular" wafer doesn't suit me at all) seems to be nontrivial, specially for more or less precise (< 30% error) cuts and unfortunately I'm not so handy (I think I will break most of them)...

Also, I saw that we can purchase the wafer with a coating but as far as can tell (which maybe is wrong), its not just for the top and bottom sides, the coating would reach every side of the wafer. Since I want to plug in a power supply to the front and back sides of the wafer, these sides need to be "accessible". Even without coating, I don't know if it possible to solder some wire directly into the silicon to connect it to the power supply...?

Another solution could be graphite or germanium plates?

Is there a better idea than the wafer? If the wafer is a "good" solution, can you recommend some (European would help) manufacturer?

If no thin (small h) solution is possible, then it could be relaxed to \$ h = 1 mm \$ if needed, but having a top/down insulator would be extremely helpful.

Also, please keep in mind that is a hobby experiment, not an application and certainly not for a commercial system so I can spend some money, but not $1000 :).

I'm doing experiments with electric fields and would (ideally) like a very thin box as shown in this picture:

It would need a very thin $h$ (of about 200 um at most, if possible), an $l$ of about 10 cm and a $w$ that would allow a resistance of about 180 ohms. Since $$ R = \rho \frac{w}{h*l} $$

that would mean w would depend on the resistivity $ \rho $ of the material.

Also, it would really help if the top and bottom surfaces are covered with an even thinner insulator (~5 um would be possible? The smaller the better).

I was thinking about a silicon wafer. Some shops sell it with an $ h ~ 130um $, $ \rho ~ 0.01 ohm * m $ , $ l ~10 cm$ which would mean $ w ~ 23cm$. But if $ \rho $ is even smaller than better (as long as $ l > 1cm $ its good so I can still work on it with my hands)

But I never bought a wafer before and dicing it (a "circular" wafer doesn't suite me at all) seems to be non trivial, specially for more or less precise (< 30% error) cuts and unfortunately I'm not so handy (I think I will break most of them)... Also, I saw that we can purchase the wafer with a coating but as far as can tell (which maybe is wrong), its not just for the top and bottom sides, the coating would reach every side of the wafer. Since I want to plug in a power supply to the front and back sides of the wafer, these sides need to be "accessible". Even without coating, I don't know if it possible to solder some wire directly into the silicon to connect it to the power supply...?

Is there a better idea than the wafer? If the wafer is a "good" solution, can you recommend some (European would help) manufacturer?

Also, please keep in mind that is a hobby experiment, not an application and certainly not for a commercial system so I can spend some money, but not 1000$ :).

I'm doing experiments with electric fields and would (ideally) like a very thin box as shown in this picture:

It would need a very thin \$h\$ (of about 200 um at most, if possible), an \$l\$ of about 10 cm and a \$w\$ that would allow a resistance of about 180 ohms. Since $$ R = \rho \frac{w}{h*l} $$

that would mean w would depend on the resistivity \$ \rho \$ of the material.

Also, it would really help if the top and bottom surfaces are covered with an even thinner insulator (~5 um would be possible? The smaller the better).

I was thinking about a silicon wafer. Some shops sell it with an \$ h ~ 130um \$, \$ \rho ~ 0.01 ohm * m \$ , \$ l ~10 cm\$ which would mean \$ w ~ 23cm\$. But if \$ \rho \$ is even smaller than better (as long as \$ l > 1cm \$ its good so I can still work on it with my hands)

But I never bought a wafer before and dicing it (a "circular" wafer doesn't suit me at all) seems to be nontrivial, specially for more or less precise (< 30% error) cuts and unfortunately I'm not so handy (I think I will break most of them)...

Also, I saw that we can purchase the wafer with a coating but as far as can tell (which maybe is wrong), its not just for the top and bottom sides, the coating would reach every side of the wafer. Since I want to plug in a power supply to the front and back sides of the wafer, these sides need to be "accessible". Even without coating, I don't know if it possible to solder some wire directly into the silicon to connect it to the power supply...?

Is there a better idea than the wafer? If the wafer is a "good" solution, can you recommend some (European would help) manufacturer?

Also, please keep in mind that is a hobby experiment, not an application and certainly not for a commercial system so I can spend some money, but not $1000 :).