公开(公告)号：US08954021B2

公开(公告)日：2015-02-10

申请号：US14303513

申请日：2014-06-12

申请人： Han Wui Then ,  Sansaptak Dasgupta ,  Marko Radosavljevic ,  Benjamin Chu-Kung ,  Sanaz Gardner ,  Seung Hoon Sung ,  Robert S. Chau

发明人： Han Wui Then ,  Sansaptak Dasgupta ,  Marko Radosavljevic ,  Benjamin Chu-Kung ,  Sanaz Gardner ,  Seung Hoon Sung ,  Robert S. Chau

IPC分类号： H04B1/04 ,  H01L29/772 ,  H01L29/20 ,  H01L29/80 ,  H01L29/66 ,  H01L29/78

CPC分类号： H01L29/2003 ,  H01L21/02164 ,  H01L21/02238 ,  H01L21/02255 ,  H01L21/0228 ,  H01L21/0254 ,  H01L21/283 ,  H01L21/28575 ,  H01L21/84 ,  H01L27/1203 ,  H01L29/0649 ,  H01L29/201 ,  H01L29/42356 ,  H01L29/66462 ,  H01L29/66795 ,  H01L29/7787 ,  H01L29/78 ,  H01L29/785 ,  H01L29/7851 ,  H01L29/802

摘要： A III-N semiconductor channel is formed on a III-N transition layer formed on a (111) or (110) surface of a silicon template structure, such as a fin sidewall. In embodiments, the silicon fin has a width comparable to the III-N epitaxial film thicknesses for a more compliant seeding layer, permitting lower defect density and/or reduced epitaxial film thickness. In embodiments, a transition layer is GaN and the semiconductor channel comprises Indium (In) to increase a conduction band offset from the silicon fin. In other embodiments, the fin is sacrificial and either removed or oxidized, or otherwise converted into a dielectric structure during transistor fabrication. In certain embodiments employing a sacrificial fin, the III-N transition layer and semiconductor channel is substantially pure GaN, permitting a breakdown voltage higher than would be sustainable in the presence of the silicon fin.

摘要翻译： III-N半导体沟道形成在形成于诸如翅片侧壁的硅模板结构的（111）或（110）表面上的III-N过渡层上。 在实施例中，硅鳍具有与更适应的种子层的III-N外延膜厚度相当的宽度，允许更低的缺陷密度和/或降低的外延膜厚度。 在实施例中，过渡层是GaN，并且半导体沟道包括铟（In）以增加从硅片的导带偏移。 在其它实施例中，鳍是牺牲性的，并且在晶体管制造期间被去除或氧化，或以其它方式转换为电介质结构。 在采用牺牲散热片的某些实施例中，III-N过渡层和半导体通道是基本上纯的GaN，允许击穿电压高于在硅片存在时可持续的击穿电压。

公开(公告)号：US20140291693A1

公开(公告)日：2014-10-02

申请号：US14303513

申请日：2014-06-12

申请人： Han Wui THEN ,  Sansaptak Dasgupta ,  Marko Radosavljevic ,  Benjamin Chu-Kung ,  Sanaz Gardner ,  Seung Hoon Sung ,  Robert S. Chau

发明人： Han Wui THEN ,  Sansaptak Dasgupta ,  Marko Radosavljevic ,  Benjamin Chu-Kung ,  Sanaz Gardner ,  Seung Hoon Sung ,  Robert S. Chau

IPC分类号： H01L29/20 ,  H01L29/78

CPC分类号： H01L29/2003 ,  H01L21/02164 ,  H01L21/02238 ,  H01L21/02255 ,  H01L21/0228 ,  H01L21/0254 ,  H01L21/283 ,  H01L21/28575 ,  H01L21/84 ,  H01L27/1203 ,  H01L29/0649 ,  H01L29/201 ,  H01L29/42356 ,  H01L29/66462 ,  H01L29/66795 ,  H01L29/7787 ,  H01L29/78 ,  H01L29/785 ,  H01L29/7851 ,  H01L29/802

摘要： A III-N semiconductor channel is formed on a III-N transition layer formed on a (111) or (110) surface of a silicon template structure, such as a fin sidewall. In embodiments, the silicon fin has a width comparable to the III-N epitaxial film thicknesses for a more compliant seeding layer, permitting lower defect density and/or reduced epitaxial film thickness. In embodiments, a transition layer is GaN and the semiconductor channel comprises Indium (In) to increase a conduction band offset from the silicon fin. In other embodiments, the fin is sacrificial and either removed or oxidized, or otherwise converted into a dielectric structure during transistor fabrication. In certain embodiments employing a sacrificial fin, the III-N transition layer and semiconductor channel is substantially pure GaN, permitting a breakdown voltage higher than would be sustainable in the presence of the silicon fin.

摘要翻译： III-N半导体沟道形成在形成于诸如翅片侧壁的硅模板结构的（111）或（110）表面上的III-N过渡层上。 在实施例中，硅鳍具有与更适应的种子层的III-N外延膜厚度相当的宽度，允许更低的缺陷密度和/或降低的外延膜厚度。 在实施例中，过渡层是GaN，并且半导体沟道包括铟（In）以增加从硅片的导带偏移。 在其它实施例中，鳍是牺牲性的，并且在晶体管制造期间被去除或氧化，或以其它方式转换为电介质结构。 在采用牺牲散热片的某些实施例中，III-N过渡层和半导体通道是基本上纯的GaN，允许击穿电压高于在硅片存在时可持续的击穿电压。

公开(公告)号：US08896101B2

公开(公告)日：2014-11-25

申请号：US13725546

申请日：2012-12-21

申请人： Han Wui Then ,  Sansaptak Dasgupta ,  Marko Radosavljevic ,  Benjamin Chu-Kung ,  Seung Hoon Sung ,  Sanaz K. Gardner ,  Robert S. Chau

发明人： Han Wui Then ,  Sansaptak Dasgupta ,  Marko Radosavljevic ,  Benjamin Chu-Kung ,  Seung Hoon Sung ,  Sanaz K. Gardner ,  Robert S. Chau

IPC分类号： H01L29/20 ,  H01L29/772 ,  H01L29/66

CPC分类号： H01L29/78696 ,  H01L21/02387 ,  H01L21/02389 ,  H01L21/02433 ,  H01L21/02458 ,  H01L21/0251 ,  H01L21/02538 ,  H01L21/0254 ,  H01L29/045 ,  H01L29/0673 ,  H01L29/2003 ,  H01L29/205 ,  H01L29/42392 ,  H01L29/66409 ,  H01L29/66522 ,  H01L29/66742 ,  H01L29/772 ,  H01L29/785 ,  H01L29/78681

摘要： A III-N semiconductor channel is compositionally graded between a transition layer and a III-N polarization layer. In embodiments, a gate stack is deposited over sidewalls of a fin including the graded III-N semiconductor channel allowing for formation of a transport channel in the III-N semiconductor channel adjacent to at least both sidewall surfaces in response to a gate bias voltage. In embodiments, a gate stack is deposited completely around a nanowire including a III-N semiconductor channel compositionally graded to enable formation of a transport channel in the III-N semiconductor channel adjacent to both the polarization layer and the transition layer in response to a gate bias voltage.

摘要翻译： III-N半导体通道在过渡层和III-N偏振层之间组成分级。 在实施例中，栅堆叠沉积在包括渐变III-N半导体沟道的鳍的侧壁上，允许在响应于栅极偏置电压的至少两个侧壁表面相邻的III-N半导体沟道中形成传输沟道。 在实施例中，栅极叠层完全沉积在包括III-N半导体沟道的纳米线周围，该纳米线被组成分级，以使得能够响应于栅极形成与偏振层和过渡层两者相邻的III-N半导体沟道中的传输沟道 偏压。

公开(公告)号：US20150206796A1

公开(公告)日：2015-07-23

申请号：US14162717

申请日：2014-01-23

申请人： Sansaptak Dasgupta ,  Han Wui Then ,  Sanaz K. Gardner ,  Seung Hoon Sung ,  Marko Radosavljevic ,  Benjamin Chu-Kung ,  Sherry R. Taft ,  Ravi Pillarisetty ,  Robert S. Chau

发明人： Sansaptak Dasgupta ,  Han Wui Then ,  Sanaz K. Gardner ,  Seung Hoon Sung ,  Marko Radosavljevic ,  Benjamin Chu-Kung ,  Sherry R. Taft ,  Ravi Pillarisetty ,  Robert S. Chau

IPC分类号： H01L21/768 ,  H01L21/762 ,  H01L21/02

CPC分类号： H01L29/2003 ,  H01L21/02381 ,  H01L21/02458 ,  H01L21/0254 ,  H01L21/02639 ,  H01L21/02647 ,  H01L21/76229 ,  H01L21/76232 ,  H01L21/8258 ,  H01L29/045 ,  H01L29/0649 ,  H01L29/0684

摘要： A trench comprising a portion of a substrate is formed. A nucleation layer is deposited on the portion of the substrate within the trench. A III-N material layer is deposited on the nucleation layer. The III-N material layer is laterally grown over the trench. A device layer is deposited on the laterally grown III-N material layer. A low defect density region is obtained on the laterally grown material and is used for electronic device fabrication of III-N materials on Si substrates.

摘要翻译： 形成包括基板的一部分的沟槽。 成核层沉积在沟槽内的衬底部分上。 在成核层上沉积III-N材料层。 在沟槽上横向生长III-N材料层。 器件层沉积在横向生长的III-N材料层上。 在横向生长的材料上获得低缺陷密度区域，并用于Si衬底上的III-N材料的电子器件制造。

公开(公告)号：US20150187924A1

公开(公告)日：2015-07-02

申请号：US14141304

申请日：2013-12-26

申请人： Sansaptak Dasgupta ,  Han Wui Then ,  Marko Radosavljevic ,  Sanaz K. Gardner ,  Seung Hoon Sung ,  Benjamin Chu-Kung ,  Robert S. Chau

发明人： Sansaptak Dasgupta ,  Han Wui Then ,  Marko Radosavljevic ,  Sanaz K. Gardner ,  Seung Hoon Sung ,  Benjamin Chu-Kung ,  Robert S. Chau

IPC分类号： H01L29/778 ,  H01L21/306 ,  H01L29/66

CPC分类号： H01L29/7783 ,  H01L21/30612 ,  H01L21/30617 ,  H01L29/155 ,  H01L29/2003 ,  H01L29/4236 ,  H01L29/66462 ,  H01L29/7786

摘要： Transistors or transistor layers include an InAlN and AlGaN bi-layer capping stack on a 2DEG GaN channel, such as for GaN MOS structures on Si substrates. The GaN channel may be formed in a GaN buffer layer or stack, to compensate for the high crystal structure lattice size and coefficient of thermal expansion mismatch between GaN and Si. The bi-layer capping stack an upper InAlN layer on a lower AlGaN layer to induce charge polarization in the channel, compensate for poor composition uniformity (e.g., of Al), and compensate for rough surface morphology of the bottom surface of the InAlN material. It may lead to a sheet resistance between 250 and 350 ohms/sqr. It may also reduce bowing of the GaN on Si wafers during growth of the layer of InAlN material, and provide a AlGaN setback layer for etching the InAlN layer in the gate region.

摘要翻译： 晶体管或晶体管层包括2DEG GaN沟道上的InAlN和AlGaN双层封装叠层，例如用于Si衬底上的GaN MOS结构。 GaN沟道可以形成在GaN缓冲层或堆叠中，以补偿GaN和Si之间的高晶格结构晶格尺寸和热膨胀失配系数。 双层封装在下AlGaN层上堆叠上InAlN层以在沟道中引起电荷极化，补偿较差的组成均匀性（例如Al），并补偿InAlN材料的底表面的粗糙表面形态。 它可能导致250和350欧姆/ sqr之间的薄层电阻。 还可以在InAlN材料层的生长期间减少Si晶片上的GaN的弯曲，并且提供用于蚀刻栅极区域中的InAlN层的AlGaN回填层。

公开(公告)号：US08768271B1

公开(公告)日：2014-07-01

申请号：US13720852

申请日：2012-12-19

申请人： Han Wui Then ,  Sansaptak Dasgupta ,  Marko Radosavljevic ,  Benjamin Chu-Kung ,  Sanaz K. Gardner ,  Seung Hoon Sung ,  Robert S. Chau

发明人： Han Wui Then ,  Sansaptak Dasgupta ,  Marko Radosavljevic ,  Benjamin Chu-Kung ,  Sanaz K. Gardner ,  Seung Hoon Sung ,  Robert S. Chau

IPC分类号： H04B1/04 ,  H01L29/772

CPC分类号： H01L29/2003 ,  H01L21/02164 ,  H01L21/02238 ,  H01L21/02255 ,  H01L21/0228 ,  H01L21/0254 ,  H01L21/283 ,  H01L21/28575 ,  H01L21/84 ,  H01L27/1203 ,  H01L29/0649 ,  H01L29/201 ,  H01L29/42356 ,  H01L29/66462 ,  H01L29/66795 ,  H01L29/7787 ,  H01L29/78 ,  H01L29/785 ,  H01L29/7851 ,  H01L29/802

摘要： A III-N semiconductor channel is formed on a III-N transition layer formed on a (111) or (110) surface of a silicon template structure, such as a fin sidewall. In embodiments, the silicon fin has a width comparable to the III-N epitaxial film thicknesses for a more compliant seeding layer, permitting lower defect density and/or reduced epitaxial film thickness. In embodiments, a transition layer is GaN and the semiconductor channel comprises Indium (In) to increase a conduction band offset from the silicon fin. In other embodiments, the fin is sacrificial and either removed or oxidized, or otherwise converted into a dielectric structure during transistor fabrication. In certain embodiments employing a sacrificial fin, the III-N transition layer and semiconductor channel is substantially pure GaN, permitting a breakdown voltage higher than would be sustainable in the presence of the silicon fin.

摘要翻译： III-N半导体沟道形成在形成于诸如翅片侧壁的硅模板结构的（111）或（110）表面上的III-N过渡层上。 在实施例中，硅鳍具有与更适应的种子层的III-N外延膜厚度相当的宽度，允许更低的缺陷密度和/或降低的外延膜厚度。 在实施例中，过渡层是GaN，并且半导体沟道包括铟（In）以增加从硅片的导带偏移。 在其它实施例中，鳍是牺牲性的，并且在晶体管制造期间被去除或氧化，或以其它方式转换为电介质结构。 在采用牺牲散热片的某些实施例中，III-N过渡层和半导体通道是基本上纯的GaN，允许击穿电压高于在硅片存在时可持续的击穿电压。

公开(公告)号：US09634007B2

公开(公告)日：2017-04-25

申请号：US14302350

申请日：2014-06-11

申请人： Ravi Pillarisetty ,  Seung Hoon Sung ,  Niti Goel ,  Jack T. Kavalieros ,  Sansaptak Dasgupta ,  Van H. Le ,  Willy Rachmady ,  Marko Radosavljevic ,  Gilbert Dewey ,  Han Wui Then ,  Niloy Mukherjee ,  Matthew V. Metz ,  Robert S. Chau

发明人： Ravi Pillarisetty ,  Seung Hoon Sung ,  Niti Goel ,  Jack T. Kavalieros ,  Sansaptak Dasgupta ,  Van H. Le ,  Willy Rachmady ,  Marko Radosavljevic ,  Gilbert Dewey ,  Han Wui Then ,  Niloy Mukherjee ,  Matthew V. Metz ,  Robert S. Chau

IPC分类号： H01L29/66 ,  H01L29/78 ,  H01L21/02 ,  H01L21/762 ,  H01L27/092 ,  H01L21/8258 ,  H01L29/423 ,  H01L29/786 ,  B82Y10/00 ,  B82Y40/00 ,  H01L29/775 ,  H01L29/06 ,  H01L21/8238

CPC分类号： H01L21/845 ,  B82Y10/00 ,  B82Y40/00 ,  H01L21/02639 ,  H01L21/823807 ,  H01L21/8258 ,  H01L27/092 ,  H01L27/1211 ,  H01L29/0673 ,  H01L29/42392 ,  H01L29/66439 ,  H01L29/6653 ,  H01L29/66795 ,  H01L29/6681 ,  H01L29/775 ,  H01L29/78 ,  H01L29/785 ,  H01L29/7853 ,  H01L29/78696

摘要： Trench-confined selective epitaxial growth process in which epitaxial growth of a semiconductor device layer proceeds within the confines of a trench. In embodiments, a trench is fabricated to include a pristine, planar semiconductor seeding surface disposed at the bottom of the trench. Semiconductor regions around the seeding surface may be recessed relative to the seeding surface with Isolation dielectric disposed there on to surround the semiconductor seeding layer and form the trench. In embodiments to form the trench, a sacrificial hardmask fin may be covered in dielectric which is then planarized to expose the hardmask fin, which is then removed to expose the seeding surface. A semiconductor device layer is formed from the seeding surface through selective heteroepitaxy. In embodiments, non-planar devices are formed from the semiconductor device layer by recessing a top surface of the isolation dielectric. In embodiments, non-planar devices CMOS devices having high carrier mobility may be made from the semiconductor device layer.

公开(公告)号：US08765563B2

公开(公告)日：2014-07-01

申请号：US13630527

申请日：2012-09-28

申请人： Ravi Pillarisetty ,  Seung Hoon Sung ,  Niti Goel ,  Jack T. Kavalieros ,  Sansaptak Dasgupta ,  Van H. Le ,  Willy Rachmady ,  Marko Radosavljevic ,  Gilbert Dewey ,  Han Wui Then ,  Niloy Mukherjee ,  Matthew V. Metz ,  Robert S. Chau

发明人： Ravi Pillarisetty ,  Seung Hoon Sung ,  Niti Goel ,  Jack T. Kavalieros ,  Sansaptak Dasgupta ,  Van H. Le ,  Willy Rachmady ,  Marko Radosavljevic ,  Gilbert Dewey ,  Han Wui Then ,  Niloy Mukherjee ,  Matthew V. Metz ,  Robert S. Chau

IPC分类号： H01L21/00 ,  H01L21/311 ,  H01L21/8222 ,  H01L21/30 ,  H01L21/20 ,  H01L29/15

CPC分类号： H01L21/845 ,  B82Y10/00 ,  B82Y40/00 ,  H01L21/02639 ,  H01L21/823807 ,  H01L21/8258 ,  H01L27/092 ,  H01L27/1211 ,  H01L29/0673 ,  H01L29/42392 ,  H01L29/66439 ,  H01L29/6653 ,  H01L29/66795 ,  H01L29/6681 ,  H01L29/775 ,  H01L29/78 ,  H01L29/785 ,  H01L29/7853 ,  H01L29/78696

摘要： Trench-confined selective epitaxial growth process in which epitaxial growth of a semiconductor device layer proceeds within the confines of a trench. In embodiments, a trench is fabricated to include a pristine, planar semiconductor seeding surface disposed at the bottom of the trench. Semiconductor regions around the seeding surface may be recessed relative to the seeding surface with Isolation dielectric disposed there on to surround the semiconductor seeding layer and form the trench. In embodiments to form the trench, a sacrificial hardmask fin may be covered in dielectric which is then planarized to expose the hardmask fin, which is then removed to expose the seeding surface. A semiconductor device layer is formed from the seeding surface through selective heteroepitaxy. In embodiments, non-planar devices are formed from the semiconductor device layer by recessing a top surface of the isolation dielectric. In embodiments, non-planar devices CMOS devices having high carrier mobility may be made from the semiconductor device layer.

摘要翻译： 沟槽限制的选择性外延生长工艺，其中半导体器件层的外延生长在沟槽的范围内进行。 在实施例中，制造沟槽以包括设置在沟槽底部的原始平面半导体晶种表面。 接种表面周围的半导体区域可以相对于接种表面凹陷，其中隔离电介质设置在其上以包围半导体晶种层并形成沟槽。 在形成沟槽的实施例中，牺牲性硬掩模翅片可以被覆盖在电介质中，然后将其平坦化以暴露硬掩模翅片，然后将其去除以暴露接种表面。 通过选择性异质外延从种子表面形成半导体器件层。 在实施例中，通过使隔离电介质的顶表面凹陷，从半导体器件层形成非平面器件。 在实施例中，可以从半导体器件层制造具有高载流子迁移率的非平面器件CMOS器件。

公开(公告)号：US09099490B2

公开(公告)日：2015-08-04

申请号：US13631534

申请日：2012-09-28

申请人： Sansaptak Dasgupta ,  Han Wui Then ,  Marko Radosavljevic ,  Niloy Mukherjee ,  Niti Goel ,  Sanaz Kabehie ,  Seung Hoon Sung ,  Ravi Pillarisetty ,  Robert S. Chau

发明人： Sansaptak Dasgupta ,  Han Wui Then ,  Marko Radosavljevic ,  Niloy Mukherjee ,  Niti Goel ,  Sanaz Kabehie ,  Seung Hoon Sung ,  Ravi Pillarisetty ,  Robert S. Chau

IPC分类号： H01L29/66 ,  H01L29/778 ,  H01L29/423 ,  H01L29/08 ,  H01L29/20

CPC分类号： H01L29/7784 ,  H01L21/0254 ,  H01L21/2233 ,  H01L21/2236 ,  H01L21/2654 ,  H01L21/26546 ,  H01L21/31111 ,  H01L21/31144 ,  H01L29/0847 ,  H01L29/2003 ,  H01L29/205 ,  H01L29/207 ,  H01L29/42376 ,  H01L29/66462 ,  H01L29/7786 ,  H01L29/7787

摘要： Embodiments include high electron mobility transistors (HEMT). In embodiments, a gate electrode is spaced apart by different distances from a source and drain semiconductor region to provide high breakdown voltage and low on-state resistance. In embodiments, self-alignment techniques are applied to form a dielectric liner in trenches and over an intervening mandrel to independently define a gate length, gate-source length, and gate-drain length with a single masking operation. In embodiments, III-N HEMTs include fluorine doped semiconductor barrier layers for threshold voltage tuning and/or enhancement mode operation.

摘要翻译： 实施例包括高电子迁移率晶体管（HEMT）。 在实施例中，栅电极与源极和漏极半导体区间隔开不同的距离以提供高击穿电压和低导通状态电阻。 在实施例中，应用自对准技术以在沟槽中和在中间心轴上形成电介质衬垫，以通过单个掩蔽操作独立地限定栅极长度，栅极源长度和栅极 - 漏极长度。 在实施例中，III-N HEMT包括用于阈值电压调谐和/或增强模式操作的氟掺杂半导体势垒层。

公开(公告)号：US08785907B2

公开(公告)日：2014-07-22

申请号：US13722746

申请日：2012-12-20

申请人： Niti Goel ,  Niloy Mukherjee ,  Seung Hoon Sung ,  Van H. Le ,  Matthew V. Metz ,  Jack T. Kavalieros ,  Ravi Pillarisetty ,  Sanaz K. Gardner ,  Sansaptak Dasgupta ,  Willy Rachmady ,  Benjamin Chu-Kung ,  Marko Radosavljevic ,  Gilbert Dewey ,  Marc C. French ,  Jessica Kachian ,  Satyarth Suri ,  Robert S. Chau

发明人： Niti Goel ,  Niloy Mukherjee ,  Seung Hoon Sung ,  Van H. Le ,  Matthew V. Metz ,  Jack T. Kavalieros ,  Ravi Pillarisetty ,  Sanaz K. Gardner ,  Sansaptak Dasgupta ,  Willy Rachmady ,  Benjamin Chu-Kung ,  Marko Radosavljevic ,  Gilbert Dewey ,  Marc C. French ,  Jessica Kachian ,  Satyarth Suri ,  Robert S. Chau

IPC分类号： H01L29/06

CPC分类号： H01L21/764 ,  H01L21/02381 ,  H01L21/0245 ,  H01L21/02494 ,  H01L21/02507 ,  H01L21/02532 ,  H01L21/76232

摘要： An embodiment includes depositing a material onto a substrate where the material includes a different lattice constant than the substrate (e.g., III-V or IV epitaxial (EPI) material on a Si substrate). An embodiment includes an EPI layer formed within a trench having walls that narrow as the trench extends upwards. An embodiment includes an EPI layer formed within a trench using multiple growth temperatures. A defect barrier, formed in the EPI layer when the temperature changes, contains defects within the trench and below the defect barrier. The EPI layer above the defect barrier and within the trench is relatively defect free. An embodiment includes an EPI layer annealed within a trench to induce defect annihilation. An embodiment includes an EPI superlattice formed within a trench and covered with a relatively defect free EPI layer (that is still included in the trench). Other embodiments are described herein.

摘要翻译： 实施例包括将材料沉积到衬底上，其中材料包括与衬底（例如Si衬底上的III-V或IV外延（EPI）材料）不同的晶格常数。 一个实施例包括形成在沟槽内的EPI层，其具有随着沟槽向上延伸而变窄的壁。 实施例包括使用多个生长温度在沟槽内形成的EPI层。 当温度变化时，在EPI层中形成的缺陷屏障在沟槽内和缺陷屏障之下包含缺陷。 缺陷屏障之上和沟槽内的EPI层相对无缺陷。 一个实施方案包括在沟槽内退火以引发缺陷湮灭的EPI层。 一个实施例包括形成在沟槽内并覆盖有相对无缺陷的EPI层（仍包含在沟槽中）的EPI超晶格。 本文描述了其它实施例。