Oxide Thin Film Heterostructures on Large Area, with Flexible Doping, Low Dislocation Density, and Abrupt Interfaces: Grown by Pulsed Laser Deposition

Table 7

Typical atomic concentrations of trace elements from combined PIXE/RBS analysis with 1.2 MeV protons (all values given in ppm) of two large-area 32.8 mm diameter ZnO thin films on sapphire. The PLD target was sintered from 99.9995 at.% ZnO powder. Films were grown with stainless steel substrate holder at growth temperature of about 650°C. Therefore, the Fe concentration is much higher at the wafer edges. Most elements are below the detection limits.

Sample*	Si	K	Ca	Ti	V	Cr	Mn	Fe	Ni	Cu
E391 c	1,342	<16	24	<11	<14	<15	20	35	<67	<153
E391 e	<901	30	28	<13	<16	28	<19	1,069	<69	<166
E392 c	<971	<30	<24	<21	<24	50	<26	<33	<104	<215
E392 e	<1,272	54	51	27	<29	85	41	206	<103	<243

*Sample no. E391 and E392, c and e stand for center and edge analysis position on the wafer, respectively.