Specific Process Knowledge/Thin film deposition/Furnace LPCVD PolySilicon/Boron doped poly-Si

Results from the acceptance test 2012

Recipe name	Deposition rate [nm/min]	Refractive index@630nm	Thickness variation on center wafer	Thickness variation along the boat	Surface roughness [nm]	Sheet resistance [Ohms/square]	Boron concentation [boron atoms/cm3]	Comments
"DOPEPOLY"	~ 4.0-4.1 (4" wafers)	1.29%-1.38% (4" wafers)	1.63%-1.81% (4" wafers)		~ 4.83, measured with AFM standard tip (273 nm layer) AFM image for surface roughness measurement. 273 nm boron doped polySi deposited using the "DOPDPOLY" recipe.	157-171, variation over boat 4.5% (4" wafers)	~ 1021 boron atoms/cm3. "Dopepoly" recipe, 30 minutes deposition, Poly-Si thickness is ~104nm, Aug. 2014. Boron concentration measured by SIMS through a boron doped poly-Si layer on 110nm Silicon dioxide, N-type Si(100) Substrate.	Run-to-run uniformity: 1.43 % (4" wafers, 3 runs)

Results from Tempress test January 2023

In January 2023 Tempress optimized the process for boron doped polysilicon again (they wanted to make some process development for a potential customer).

The depositions were done with 25 wafers in the furnace. Only 6" wafers were used.

The process parameters and the injector design that Tempress came up with will replace the old "DOPEPOLY" recipe from the acceptance test.

The results in table below are from run number 10.

Recipe name	Temperature [C] (zone 1, 2, 3, 4, 5)	Gas flows [sccm]	Pressure [mTorr]	Deposition rate [nm/min]	Deposition rate - Uniformity over one wafer	Deposition rate - Uniformity over boat	Sheet resistance [Ohms/square]	Sheet resistance - Uniformity over one wafer	Sheet resistance - Uniformity over the boat
"POLYBOR"	600, 596, 597, 600, 600	SiH4 (through injector): 50 BCl3 (through injector): 2	150	~ 4.15 (6" wafers)	2.9 % (door side) 1.3 % (pump side)	0.5 %	9.4 (door side) 10.01 (pump side)	1.6 % (door side) 2.0 % (pump side)	3.6 %