Robert C. Keller

Growth of Sn thin films on CdTe(111)

The formation and the growth of Sn films on CdTe(111) have been studied by hemispherically recorded ARXPS. The XPD patterns show that these films consist of α-Sn. XPD and ARXPS depth profile analysis reveal the presence of an intermixing zone at the interface which establishes during the initial stages of film formation.

A 14-bit 8.9GS/s RF DAC in 40nm CMOS achieving >71dBc LTE ACPR at 2.9GHz

We show for the first time an 8.9 GS/s RF current-steering DAC, with an on-chip 1:1 Balun, and an 8-lane 12.5 Gbps JESD204B compliant SerDes, with a measured LTE ACPR >71 dBc in the adjacent 20 MHz band for a 2.9 GHz channel. The DAC has IM3 <;-65 dBc for output frequencies up to Nyquist. This performance is accomplished using a novel DAC switch driver and data/dummy-data scheme to minimize the pattern dependent sourcing/sinking of current on the DAC driver supply and ground. The DAC is fabricated in a 40nm dual-oxide CMOS process and dissipates 1.2W, with the contribution of the synthesized digital block and SerDes excluded.