Herein we describe theoretical and experimental analysis of the source resistance (R_s) components in In_0.7Ga_0.3As/In_0.52Al_0.48As quantum-well (QW) high-electron-mobility transistors (HEMTs) on an InP substrate. First, we analytically modeled R_s using a three-layer formula, separately modeling the regions of the ohmic contact, the gate-to-source access, and the side-recessed regions. The resistances of the ohmic contact and access regions were analyzed in a distributed-network manner with two different transfer lengths, whereas the resistance associated with the side-recess region near the gate edge was modeled by using a lumped element. To verify the accuracy of the proposed R_s model, we fabricated two different types of transmission-line-method (TLM) test patterns as well as long-channel In_0.7Ga_0.3As/In_0.52Al_0.48As QW HEMTs, and compared their measured and modeled R_s. The modeled R_s was in excellent agreement with the measured R_s from the recessed TLM patterns and the long-channel HEMTs. Since the widths of the ohmic contact to the heavily doped In_0.53Ga_0.47As capping layer and the gate-to-source access region were typically much greater than corresponding transfer lengths (\(L_{{{\text{T}}\_{\text{cap}}}}\) and \(L_{{{\text{T}}\_{\text{barrier}}}}\)), those distributed networks could be simplified to a lumped-element based one-layer model, revealing that the tunneling resistance (\(R_{{{\text{barrier}}}}\)) through the In_0.52Al_0.48As barrier should be carefully considered to minimize the R_s of In_xGa_1−xAs QW HEMTs together with S/D contact resistances and L_GS.

本文中，我们描述了InP衬底上In _0.7 Ga _0.3 As / In _0.52 Al _0.48 As量子阱（QW）高电子迁移率晶体管（HEMT）中源电阻（R _s）分量的理论和实验分析。首先，我们对R _s进行了分析建模使用三层公式，分别对欧姆接触，栅极到源极访问和侧面凹陷区域进行建模。以分布网络的方式使用两种不同的传输长度来分析欧姆接触区和访问区的电阻，而通过使用集总元件来模拟与靠近栅极边缘的侧凹区相关的电阻。为了验证所提出的R _s模型的准确性，我们制造了两种不同类型的传输线方法（TLM）测试图以及长通道In _0.7 Ga _0.3 As / In _0.52 Al _0.48 As QW HEMT，并对其进行了比较测量和建模的R _s。建模的R_s与凹陷的TLM模式和长通道HEMT中测得的R _s非常吻合。由于与重掺杂In _0.53 Ga _0.47 As覆盖层和栅极到源极访问区的欧姆接触的宽度通常比相应的传输长度大得多（\（L _ {{{\ text {T}} \ _ {\ text {cap}}} \）和\（L _ {{{text {T}} \ _ {\ text {barrier}}}} \）），可以将这些分布式网络简化为集总元素基于一层的模型，揭示了通过In _0.52 Al _0.48的隧穿电阻（\（R _ {{{\ text {barrier}}}} \））应仔细考虑作为势垒，以尽量减小In _x Ga _{1- x} As QW HEMT的R _s以及S / D接触电阻和L _GS。