Development and Characterization of High-Quality HfO₂/InGaAs MOS Interface

Abstract

The scope of this chapter is to introduce a highly efficient HfO2 atomic layer deposition (ALD) process with superior interface defect characteristics that can be applied on high-mobility III-V substrates. For a long time, the major academic research of III-V metal-oxide-semiconductor (MOS) studies was mainly oriented on searching for the suitable high-k dielectric, and among the reported high-k/III-V MOS studies, Al2O3 and AlN have demonstrated the most promising results. However, usually, the dielectrics with higher dielectric constant suffered from more defective interface quality including the HfO2, which should be overcome to meet the intensive operation voltage scaling requirements. In order to protect the interface of the HfO2/III-V MOS, the exposed III-V surface has to be carefully treated before, while, and after the whole high-k deposition process. For this purpose, the effect of isopropyl alcohol precursor and in situ cyclic nitrogen plasma treatment on the HfO2 ALD process at III-V substrates was thoroughly investigated. Remarkable interface state density levels with strong inversion behavior were achieved, which have not been observed at the previous HfO2/InGaAs studies. Also, detailed analysis of the interface characteristics was investigated to broaden the understanding of the improvement phenomenon.

Oxide/InAs(001) interface passivation with fluorine

“…The most widespread current method of formation of these interfaces is the atomic layer deposition (ALD) of dielectrics with a high permittivity (high-k) preceded by the removal of native oxide and other chemical treatment procedures aimed at passivation of the semiconductor surface. Although the amount of semiconductor oxides decreases in the first ALD cycles under the influence of the main precursor ( " self-cleaning"effect) [4], it is rather hard to remove them completely [5], not least because of the possible reoxidation of a semiconductor by an oxidizer [6].…”

Влияние фтора на плотность состояний на границе раздела анодный оксидный слой/In-=SUB=-0.53-=/SUB=-Ga-=SUB=-0.47-=/SUB=-As

“…In 0.53 Ga 0.47 As применяется для изготовления МОПтранзисторов (МОП -металл−оксид−полупроводник) с высокой подвижностью электронов [1,2], при реализации которых одним из основных требований является низкая плотность электронных состояний (D it ) на границе раздела диэлектрик/InGaAs [3]. В настоящее время для формирования таких границ в основном используется ex situ метод атомно-слоевого осаждения high-k диэлектриков, таких как Al 2 O 3 [4,5], HfO 2 [6], Y 2 O 3 [7], La 2 O 3 [8] и других [3], в сочетании с различными предварительными химическими обработками поверхности полупроводника, а также условиями осаждения диэлектрических слоев и их последующего отжига. Минимально достигнутые значения D it вблизи середины запрещенной зоны, полученные методом проводимости, составляют (4−5) • 10 11 eV −1 • cm −2 [6][7][8].…”