Characterization and Control of Metal/GaN and Insulator/GaN Interfaces for Fabrication of MIS Field Effect Transistors

对MIS场效应晶体管的金属/GaN （M-S）和绝缘体/GaN （I-S）接口的电气性能进行了调查。M-S接口的特性; （1）金属/GaN接口的费米水平是不确定的，Schottky屏障高度（SBH）是由金属工作功能决定的。（2） Reported large discrepancies in the SBH's between I-V and C-V measurements，scManagement ed Richardson constants， temperature-dependent SBH， and appearance of I-V shoulder are well Management ained by additional leakage current Management from small“patchy”defect regions with low SBH's。（3）n-和p-GaN SBH在室内温度上的总和不如小，与GaN带隙相比较，而当GaN带隙接近于高温下的GaN带隙。These phenomena can be again explained by the proposed "patchy" model. 2。I-S接口的特性;对Al/PCVD-SiO-D22-D2/n-GaN结构的C-V测量，其接口Fermi水平位置约0.3 eV，从热均衡条件下的条件带边缘，它可以在上Forbidden带间隙与应用栅极偏差的情况下移动，并指示MISFET器件的可行性。一个相对较小的波段弯曲用于n-GaN表面也是从C-t测量证实的。M-S和I-S接口的改进; SBH的统一性在N-D22-D2 （400-500 ° C）中得到了极大的改进，没有Schottky字符学的任何退化。观察到的I-V型肩膀被认为是一个相当好的N值。For the I-S interface， a brief annealing in H-D22（300-500℃）具有很高的效果， and the minimum interface state density is reduced below 1 X10-D111 cm D1-2 EV D1-1 EV D1-1 ED 1 ED

Electrical properties of metal/GaN (M-S) and insulator/GaN (I-S) interfaces have been investigated for the fabrication of MIS Field Effect Transistors.1. Characterization of M-S interfaces; (1) Fermi level at metal/GaN interface is unpinned, and the Schottky barrier height (SBH) is predominantly determined by the metal work function. (2) Reported large discrepancies in the SBH's between I-V and C-V measurements, scattered Richardson constants, temperature-dependent SBH, and appearance of I-V shoulder are well explained by additional leakage current arising from small "patchy" defect regions with low SBH's. (3) The sum of n- and p-GaN SBH's at room-temperature is rather small as compared with the GaN band gap while it becomes close to the GaN band gap at high-temperatures. These phenomena can be again explained by the proposed "patchy" model.2. Characterization of I-S interfaces; C-V measurements of Al/PCVD-SiOィイD22ィエD2/n-GaN structures revealed that the interface Fermi level locates at around 0.3 eV from the conduction band edge under thermal equilibrium condition and it can move within the upper forbidden band gap with the applied gate bias, indicating the feasibility of MISFET devices. A relatively small band bending for n-GaN surface was also confirmed from C-t measurement.3. Improvement of M-S and I-S interfaces; The uniformity of the SBH is greatly improved by an annealing in NィイD22ィエD2 (400-500℃), without any degradation of the Schottky characteristics. The observed I-V shoulder was considerably reduced with a fairly good n-value. For the I-S interface, a brief annealing in HィイD22ィエD2 (300-500℃) is highly effective to improve the interface properties, and the minimum interface state density is reduced below 1 X 10ィイD111ィエD1 cmィイD1-2ィエD1eVィイD1-1ィエD1