D.C. Shye

Trench MOS barrier Schottky rectifier formed by counter-doping trench-bottom implantation

Abstract A trench MOS barrier Schottky (TMBS) rectifier has been formed by carrying out trench bottom counter-doping implantation for improving the blocking voltage and the device reliability. By additionally implementing a counter-doped region enclosing the trench bottom, the reverse blocking voltage of the conventional TMBS rectifier can be significantly enhanced without considerable degradation of on-state characteristics. In addition, the device reliability can be significantly improved. The large peak electric field in the corner of trench bottom, which limits the blocking voltage of the conventional TMBS rectifier, can be largely alleviated due to charge compensation. Though the counter-doped region enclosing the trench bottom may partly encroach into the mesa region, no considerable deterioration of on-state characteristics is caused. In addition, a too low-dose trench-bottom implantation cannot provide sufficient charge compensation, and a too high-dose trench-bottom implantation would create a large peak electric field below the trench bottom. As a result, a proper trench-bottom implantation may be employed to significantly enhance the blocking voltage without considerable degradation of on-state characteristics.

Annealing effect on hydrothermally grown ZnO thin-film transistors

High-performance zinc oxide (ZnO) thin-film transistors (TFTs) with location-controlled lateral grain were fabricated by low-temperature hydrothermal method. The ZnO active channel was laterally grown with aluminum-doped ZnO (AZO) seed layer underneath the Ti/Pt film. The annealed ZnO TFTs reveal high-quality ZnO films with the compensated structural defects in the channel region compared to the unannealed devices. Thus, the superior device performances (i.e. the excellent μFE of 9.07 cm2/V·s, high on/off current ratio of ∼ 106, and low gate leakage current of < 1 nA) of hydrothermal growth (HTG) ZnO TFTs can be achieved after annealing.