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• Statistical Inference 统计推断
• Statistical Computing 统计计算
• (Generalized) Linear Models 广义线性模型
• Statistical Machine Learning 统计机器学习
• Longitudinal Data Analysis 纵向数据分析
• Foundations of Data Science 数据科学基础

## 电子工程代写|超大规模集成电路系统代写Introduction to VLSI Systems代考|Cell Designs

The essence of hierarchical design is the capability of reusing some basic cells over and over again. During the course of bottom-up composition, a group of cells may be combined into a submodule and it can be in turn used as a submodule for another higher-level submodule. This process continues until the entire system is constructed. Therefore, the basic building blocks are cells. But what kind of circuit can be referred to as a cell? How complex a function should it contain? In fact, the function of a cell could range from a simple gate to a very complicated module, such as an MP3 decoder or even a 32-bit microprocessor.

In the following, we will introduce the three most basic types of cells corresponding to those often introduced in basic texts: combinational cells, sequential cells, and subsystem cells. Their details will be treated in greater detail in dedicated chapters later in the book.

Combinational cells are logic circuits whose outputs are only determined by the present inputs, i.e., only functions of present inputs. The most basic CMOS circuit is the NOT gate (i.e., inverter), which is composed of two MOS transistors, a pMOS transistor, and an nMOS transistor, as shown in Figure $1.34(\mathrm{a})$. The pMOS transistor connects the output to $V_{D D}$ when it is on whereas the nMOS transistor connects the output to ground when it is on. Since both MOS transistors cannot be turned on at the same time, there is no direct path from power $\left(V_{D D}\right)$ to ground. Hence, the power dissipation is quite small, only due to a small leakage current and the transient current during switching. The average power dissipation is on the order of nanowatts. The layout and side view of a CMOS inverter are shown in Figure 1.35.

## 电子工程代写|超大规模集成电路系统代写Introduction to VLSI Systems代考|CMOS Processes

A CMOS process is a manufacturing technology capable of incorporating both pMOS and nMOS transistors in the same chip. Due to ultra-low power dissipation and high integration density, CMOS processes have become the major technology for modern VLSI circuits.

A specific CMOS circuit can be fabricated in a variety of ways. Figure $1.42$ shows the three most commonly used CMOS fabrication structures. Figure $1.42(\mathrm{a})$ is an $n$ well (or $n$-tub) structure, where an $n$-well is first implanted and then a pMOS transistor is built on the surface of it. The nMOS transistor is built on top of the $p$-type substrate. Of course, a CMOS circuit can also be built with a $p$-well on an $n$-type substrate. However, this process yields an inferior performance to the $n$-well process on the $p$ type subsirale. Hence, it is not widely used in industry.

In the $n$-well structure, the $n$-type dopant concentration must be high enough to overcompensate for the $p$-type substrate doping in order to form the required $n$-well. One major disadvantage of this structure is that the channel mobility is degraded because mobility is determined by the total concentration of dopant impurities, including both $p$ and $n$ types.

To improve channel mobility, most recent CMOS processes used in industry are the structure called a twin-well structure or a twin-tub, as shown in Figure 1.42(b). In this structure, a $p$-type epitaxial layer is first grown and then the desired $p$-type and $n$-type wells are separately grown on top of the epitaxial layer. Finally, the nMOS and pMOS transistors are then manufactured on the surface of $p$-type and $n$-type wells, respectively. The field-oxide is grown by using local oxidation of silicon (LOCOS). Due to no overcompensation problem, a high channel mobility can be achieved.

The third CMOS structure shown in Figure 1.42(c) is still a twin-well structure but uses shallow trench isolation (STI) instead of LOCOS. Due to the lack of a bird’s beak effect occurring in LOCOS, it can provide higher integration density. This structure is widely used in deep submicron (DSM) processes, in particular, below $0.18 \mu \mathrm{m}$. The STI used here has a depth less than $1 \mu \mathrm{m}$. Some processes use a deep-trench isolation with a depth deeper than the depth of a well. In such a structure, an oxide layer is thermally grown on the bottom and side walls of the trench. The trench is then refilled by depositing polysilicon or silicon dioxide. The objective of this structure is to eliminate the inherent latch-up problem associated with CMOS processes. The latch-up problem is dealt with in more detail in Chapter $4 .$

# 超大规模集成电路系统代考

## 电子工程代写|超大规模集成电路系统代写Introduction to VLSI Systems代考|CMOS Processes

CMOS 工艺是一种能够在同一芯片中集成 pMOS 和 nMOS 晶体管的制造技术。由于超低功耗和高集成度，CMOS工艺已成为现代VLSI电路的主要技术。

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## MATLAB代写

MATLAB 是一种用于技术计算的高性能语言。它将计算、可视化和编程集成在一个易于使用的环境中，其中问题和解决方案以熟悉的数学符号表示。典型用途包括：数学和计算算法开发建模、仿真和原型制作数据分析、探索和可视化科学和工程图形应用程序开发，包括图形用户界面构建MATLAB 是一个交互式系统，其基本数据元素是一个不需要维度的数组。这使您可以解决许多技术计算问题，尤其是那些具有矩阵和向量公式的问题，而只需用 C 或 Fortran 等标量非交互式语言编写程序所需的时间的一小部分。MATLAB 名称代表矩阵实验室。MATLAB 最初的编写目的是提供对由 LINPACK 和 EISPACK 项目开发的矩阵软件的轻松访问，这两个项目共同代表了矩阵计算软件的最新技术。MATLAB 经过多年的发展，得到了许多用户的投入。在大学环境中，它是数学、工程和科学入门和高级课程的标准教学工具。在工业领域，MATLAB 是高效研究、开发和分析的首选工具。MATLAB 具有一系列称为工具箱的特定于应用程序的解决方案。对于大多数 MATLAB 用户来说非常重要，工具箱允许您学习应用专业技术。工具箱是 MATLAB 函数（M 文件）的综合集合，可扩展 MATLAB 环境以解决特定类别的问题。可用工具箱的领域包括信号处理、控制系统、神经网络、模糊逻辑、小波、仿真等。

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