Dielectric/Semiconductor Interfacial p‐Doping: A New Technique to Fabricate Solution‐Processed High‐Performance 1 V Ambipolar Oxide Transistors

Abstract

Herein, dielectric/semiconductor interfacial p‐doping is used to develop a high‐carrier‐mobility and balanced ambipolar tin oxide (SnO2) thin‐film transistor (TFT). To introduce this interfacial doping, TFTs are fabricated by using two different ion‐conducting oxide dielectrics containing trivalent atoms. These ion‐conducting dielectrics are LiInO2 and LiGaO2 containing a mobile Li+ ion that reduces the operating voltage of these TFTs to ≤2.0 V. During SnO2 thin film deposition, the interfacial SnO2 layer is p‐doped by an In or Ga atom of the gate dielectric and therefore, hole conduction is facilitated in the channel of the TFT. To realize this interfacial doping phenomenon, a reference TFT is fabricated with a Li2ZnO2 dielectric that contains a divalent zinc atom. Comparative electrical data indicate that TFTs with LiInO2 and LiGaO2 dielectrics are ambipolar in nature, whereas the TFT with a Li2ZnO2 dielectric is a unipolar n‐channel transistor, corroborating the interfacial doping of SnO2. Most interestingly, using a LiInO2 dielectric, a 1.0 V balanced ambipolar TFT with high electron and hole mobility values of 7 and 8 cm2 V−1 s−1, respectively, can be fabricated, with an on/off ratio > 102 for both operations. The TFT with a LiInO2 dielectric is utilized successfully to fabricate a low‐voltage complementary metal–oxide–semiconductor (CMOS) inverter.