X-ray Photoelectron Spectroscopy (XPS) is an inspection technique to used for quantitative determine atomic composition and its chemistry located near the sample surface. The working principle is irradiating a monochromatic X-rays on the sample to kick out photoelectrons and measure the kinetic energy of electrons to determine core level of elements which these electrons come from.

Soft X-ray Photoelectron Spectroscopy (SX-XPS, 0.15~2 keV)

同步輻射光源的優點在於，可以非常方便的調整入射樣品的X光能量。依據左圖的電子動能與平均自由路徑的圖示來看，不同的X光能量，其所檢測的樣品有效深度也將改變。

傳統實驗室的XPS縱深分析，必須搭配離子束處理來去除表面材料，才能量測較深層的訊號，然而這樣也破壞了樣品結構，並可能影響樣品的特性。

同步輻射XPS可以利用連續的能量調整來探測不同深度的樣品訊號，並且無須破壞樣品的表層結構，從而保證樣品結構的完整性以及訊號的真實性。

Beamline Specifications
*Item*	*Value*	*Note*
X-ray Energy (keV)	0.15 ~ 2	G1 (500 l/mm): 0.7~2 G2 (1000 l/mm): 1~2 G3 (500 l/mm): 0.15~0.7
X-ray Spot Size (mm)	1 x 1
X-ray Flux (photon/sec)	1 x 10⁹ ~ 2 x 10¹⁰	See figure
Sample Plate Size (mm)	15 x 18 (Usable 14 x 14)	Maximum sample size limited to 12 x 12 mm
Detector	PHOIBOS 150 CCD	SPECS

Transfer Vessel Specifications
*Item*	*Value*	*Note*
Transfer Condition	Purge N2 gas	Sample will prepare and mounted on sample plate in groove box with dry N2 flow at low oxygen and water vapor condition
Maximum Sample Plate	7	Each plate can mount 1~4 sample depend on its size
Maximum Sample Height (mm)	5
Material of Sample Plate	Al, Fe, Mo, Ti, Ta	Depend on measure energy of X-rays

Experimental Details
*Item*	*Value*	*Note*
Pumping Down Time (min)	60	Maximum 7 sample plate in one vacuum vessel
Sample Transfer Time (min)	15 / 15	In and out of analysis and load-lock chamber
Sample Alignment Time (min)	5	This will be apply multi-times when change energy
Change Grating (min)	10	Exchange between G1, G2, and G3 gratings
Change Probe Energy (min)	10	For depth profiling (3-spectra for 20 min and 5-spectra for 40 min)
Spectrum Scan Time (min)	5 ~ 15	5-scan average, cover 20 eV range
Detection Limit (ppm)	< 1	Need longer aquicticon time

Soft X-ray Photoelectron Spectroscopy (SX-XPS, 0.15~2 keV)